WOOD FLOORING INSTALLATION GUIDELINES
Revised © 2019 NATIONAL WOOD FLOORING ASSOCIATION TECHNICAL PUBLICATION WOOD FLOORING INSTALLATION GUIDELINES
1 INTRODUCTION 87 SUBSTRATES: Radiant Heat
2 HEALTH AND SAFETY 102 SUBSTRATES: Existing Flooring Personal Protective Equipment Fire and Extinguisher Safety 106 UNDERLAYMENTS: Electrical Safety Moisture Control Tool Safety 110 UNDERLAYMENTS: Industry Regulations Sound Control/Acoustical 11 INSTALLATION TOOLS 116 LAYOUT Hand Tools Working Lines Power Tools Trammel Points Pneumatic Tools Transferring Lines Blades and Bits 45° Angles 19 WOOD FLOORING PRODUCT Wall-Layout Wood Flooring Options Center-Layout Trim and Mouldings Lasers Packaging 121 INSTALLATION METHODS: Conversions and Calculations Nail-Down 27 INVOLVED PARTIES 132 INSTALLATION METHODS: 29 JOBSITE CONDITIONS Glue-Down Exterior Climate Considerations 140 INSTALLATION METHODS: Exterior Conditions of the Building Floating Building Thermal Envelope Interior Conditions 145 INSTALLATION METHODS: 33 ACCLIMATION/CONDITIONING Parquet Solid Wood Flooring 150 PROTECTION, CARE Engineered Wood Flooring AND MAINTENANCE Parquet and End-Grain Wood Flooring Educating the Customer Reclaimed Wood Flooring Protection 38 MOISTURE TESTING Care Maintenance Temperature/Relative Humidity What Not to Use Moisture Testing Wood Moisture Testing Wood Subfloors 153 REPAIRS/REPLACEMENT/ Moisture Testing Concrete Subfloors REMOVAL Repair 45 BASEMENTS/CRAWLSPACES Replacement Floating Floor Board Replacement 48 SUBSTRATES: Wood Subfloors Lace-Out/Lace-In 61 SUBSTRATES: Concrete Subfloors Addressing Water Damage 161 GLOSSARY 76 SUBSTRATES : Wood Subfloor Systems Over Concrete 176 SOURCES/CREDITS
81 SUBSTRATES: Screeds/Sleepers
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NOTICE
The National Wood Flooring Association assumes no responsibility and accepts no liability for the principles or techniques contained in these guidelines/methods. These guidelines and methods for the installation of wood flooring were developed by the NWFA Technical Publications Committee, together with leading industry authorities, through review of longstanding installation principles, along with research and data regarding wood flooring installation. These guidelines and methods address a variety of ancillary products and components related to the installation of wood flooring, but are not intended to address issues arising to or from those components directly.
While every effort has been made to produce accurate and generally accepted guidelines, the principles and practices described in this publication are not universal requirements and may change. The recommendations in these guidelines/methods are directed at the North American market in general, and therefore may not necessarily reflect the most-accepted industry practices in other geographic areas. Some installation methods and materials may not be suitable in some geographic areas because of local trade practices, climatic conditions, or construction methods. All wood flooring installations must conform to local building codes, ordinances, HOA CC&Rs (Covenants, Conditions and Restrictions), trade practices, and climatic conditions.
In addition, manufacturers’ recommendations for installation of specific products should always supersede the recommendations contained in these guidelines.
It is recommended that all wood flooring products be installed in accordance with the NWFA Installation Guidelines and all applicable manufacturer instructions by an NWFACP Certified Installer, NWFA member, or equivalent.
© Copyright 2019. National Wood Flooring Association. St. Louis, Missouri, U.S.A. All rights reserved under both international and Pan American copyright conventions.
© 2019 NATIONAL WOOD FLOORING ASSOCIATION NATIONAL WOOD FLOORING ASSOCIATION TECHNICAL PUBLICATION INTRODUCTION
One of the many benefits of wood flooring is that, when installed and maintained properly, they are the only flooring option that can last for hundreds of years. In fact, there are documented wood floors in Europe that date back more than five centuries. Wood flooring can be maintained and restored to its original appeal after decades of wear and use.
Even the finest carpets will wear out after only a few years of traffic. Tile and stone can crack or chip when something gets dropped on them, and grout can crack and stain over time. Plastic and vinyl flooring can suffocate the home, and are generally designed to be disposable.
Those who work with wood floors for a living know that installing them is not a DIY job. You have to have the right tools, the right subfloor, the right jobsite conditions, and the right skills to have a successful installation. Wood flooring professionals who receive the proper training, and have the necessary industry knowledge, will be well-prepared for nearly any job they encounter.
Wood flooring is available in a wide range of options, including species, widths, thicknesses, shapes and sizes, and even different levels of hardness and dimensional stabilities. Each of these options necessitate an understanding and careful consideration for proper installation of the products. There are a number of processes that must be correctly undertaken in order to achieve a floor with the performance and appearance that is of professional standards.
These Guidelines outline the industry-accepted methods and procedures for wood flooring installations. The information included has been organized in a way that will contribute to a successful installation.
Hands-on and Online Education Available through NWFA University The National Wood Flooring Association offers online and hands-on training courses for wood flooring professionals through NWFA University. There is a comprehensive selection of technical education for professionals at all skill levels: Basic, Intermediate, Advanced, Craftsman, and Master Craftsman. For more information, contact NWFA at: [P] 800.422.4556 [W] www.nwfa.org
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Before starting any installation job, certain basic standards of safety must be applied. It is important that all crew members are briefed and updated on all requirements and regulations. This is important for the safety of you, the crew, the customer, and the jobsite. Before considering going out to install a wood floor, it is imperative to be aware of the safety issues involved. Besides being a vital health issue, following safety regulations is also required by law. Failure to comply can cost you thousands of dollars in fines.
injuries alone cost more than $300 million per year in lost production time, medical expenses, and worker compensation. OSHA requires employers to ensure the safety of all employees in the work environment. Eye protection must be provided whenever necessary to protect against chemical, environmental, radiological, or mechanical irritants and hazards. Good eye protection is meant to: • Provide adequate protection against the particular hazards for which they are designed. • Be of safe design and construction for the work The Occupational Safety and Health Administration to be performed. (OSHA) administers rules that aim to protect the safety • Be reasonably comfortable when worn under of workers on the jobsite. These rules may vary the designated conditions. according to whether the job is residential or • Fit snugly and not unduly interfere with the commercial, and requirements are also different for movements of the wearer. homeowners and professionals. Check OSHA requirements in your area at www.osha.gov. • Be durable. • Be capable of being disinfected and easily cleanable. PART I • Be distinctly marked to facilitate identification Personal Protective of the manufacturer. In addition: Equipment • Workers who wear prescription eye glasses must Personal protective equipment (PPE) is essential to also wear required eye protection. keeping you safe on the wood flooring jobsite. There • Eye protection often fits comfortably over glasses. are six main types of personal protective equipment • Safety goggles and safety glasses may designed for wood flooring professionals: incorporate prescription lenses as well. • Dust and chemicals present additional hazards to contact wearers. OSHA recommends that workers have an extra pair of contacts or eyeglasses in case of failure or loss. Ear Protection Use of ear protection is very important due to the high decibel of many of the tools used in the wood flooring industry. Each hearing protection device has a noise reduction rating (NRR). The higher the number, the greater the decibel reduction. Which type of hearing protection you choose depends on a number of factors including level of noise, comfort, and suitability of the hearing protector. Most importantly, the hearing Eye Protection protector should provide the desired noise reduction. Thousands of people are blinded each year from work- According to OSHA, people should wear a hearing related eye injuries that could have been prevented protector if the noise or sound level at the workplace with the proper selection and use of eye protection. Eye exceeds 85 decibels (A-weighted) or dBA.
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Ear protection for wood flooring professionals generally the amount of contaminants in the air. Check comes in two types: with the manufacturer of the filter or cartridge A. Ear Muffs: Ear muffs for proper storage and service life consist of sound- recommendations. attenuating material and C. Full-Facepiece Elastomeric Respirators: soft ear cushions that fit Like the half-mask elastomeric respirator, this around the ear and hard respirator is a tight-fitting, outer cups. They are held air-purifying respirator together by a head band. with replaceable filters B. Ear Plugs: Ear plugs are inserted into the ear or cartridges attached canal to block sound. They may be pre-molded to a rubber or silicone (preformed) or moldable (foam). Insert ear plugs facepiece. It needs to as follows: be fit tested. The useful • Roll the ear plug into a small crease-free service life of the filter or cylinder. cartridges is how long it • Reach over the head provides adequate protection from harmful to pull up and back on chemicals in the air. The service life of a filter or the ear to straighten cartridge depends upon many factors including the ear canal. environmental conditions, breathing rate, • Insert the ear plug cartridge filtering capacity, and the amount snugly. of contaminants in the air. Check with the manufacturer of the filter or cartridge for proper storage and service life recommendations. Respiratory Protection The respirators utilized in the wood flooring industry Knee Protection are used for the removal of contaminants from the air. Respirators of this type include disposable particulate It is extremely important to protect your knees when respirators, which filter airborne particles, and air- doing any type of wood flooring work. When installing purifying respirators with cartridges/canisters, which or finishing wood floors, you spend a lot of time on your filter out chemicals and gases. It is important to note knees. This position forces your body weight to the that a full beard will not allow masks to fully protect joints of your knees as well as the added weight of the against particles, vapors, or gases entering the lungs. equipment. Knee pads are the solution to preventing There are three main types of respirators used in the occupational knee injuries. Unprotected, sore knees wood flooring industry: force overcompensation in order to use your knees less. This means that you are transferring the weight A. Disposable Particulate Respirators: Wood that would have been on your knees to your lower back. dust becomes a potential health problem The result is a sore back and sore knees. Be sure to when wood particles from processes such as use knees pads that are comfortable and protect your sanding and cutting become airborne. Breathing knees from injury. Avoid knee pads with a hard surface these particles may cause allergic respiratory that may mar the flooring surface. There are many symptoms, mucosal and non-allergic respiratory different types of symptoms, and cancer. Proper use of a knee pads available. disposable particulate respirator minimizes the The function of all effects of these airborne particulates, but does knee pads is the not protect against gases or vapors. same: to prevent B. Half-Facepiece Elastomeric Respirators: knee injury and to Half-facepiece elastomeric respirators are protect your knees attached to a rubber or silicone facepiece that on the job. covers the nose and mouth. This type of respirator needs to be fit tested. Gloves It can be cleaned, decontaminated, Disposable gloves are used to protect the skin from and reused. The chemical exposure. They are made of different useful service life polymers including latex, of the filter or nitrile rubber, vinyl, and cartridges is how neoprene. Protective long it provides gloves should be used adequate protection when handling adhesives, from harmful chemicals in the air. The service sealers or solvents of life of a filter or cartridge depends upon many any type. Check with factors, including environmental conditions, your manufacturer for breathing rate, cartridge filtering capacity, and
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specific recommendations for protection from specific chemicals. Gloves should always be removed before using saws or other large tools that can potentially catch in machines.
Jobsite/Construction Zone Protection Any worker entering construction areas is required to wear construction zone protection. This is applicable to commercial and residential jobsites, as well as new and existing construction. A. Footwear: Construction workers should always wear work shoes or boots with slip-resistant and puncture-resistant soles. It’s also a good idea to wear safety-toed boots to prevent crushed toes. These are often made with steel-toed features. Good foot protection is also key outside of construction zone jobsites. When installing wood floors, proper work shoes can protect from Different types of fire extinguishers are designed to boards and other fight different classes of fires. equipment damaging The three most common types of fire extinguishers are: the foot. Boots and A. Water: These extinguishers are also called Air shoes should also Pressurized Water or APW extinguishers. They be non-marking to are designed for Class A fires only. prevent scuffing and scratching finished B. Carbon Dioxide or CO2: These extinguishers are floors. designed for Class B & Class C fires only. B. Hardhats: Hard hats are an essential piece of C. Dry Chemical: These extinguishers are also called personal protective equipment in a construction ABC, BC, and DC extinguishers. They are designed zone. When worn properly, they can protect for Class A, B, or C fires. Dry chemical is the type against bumps to the head from fixed or falling of extinguisher required for the objects and can protect your head from making hardwood flooring industry. accidental contact with electrical hazards. It is ABC fire extinguishers, also referred important to inspect hard hats regularly. Hard to as dry chemical extinguishers, are hats should be routinely inspected for dents, clearly labeled on each extinguisher. cracks or other signs of deterioration. Always They are designed to put out fires by replace hard hats after sustaining a heavy blow coating the fuel with a thin layer of or electrical shock. dust, thus separating the fuel from the oxygen in the air. The powder works to interrupt the chemical reaction of PART II the fire. While installing hardwood floors, it Fire and Extinguisher is important you keep fire extinguishers on hand. The Safety extinguisher must be ABC-rated in order to handle the Understanding how fire works will help promote fire potential fires that could happen on the jobsite. safety. Fire safety is based upon keeping fuel sources and ignition sources away from each other. Three Class A Fires things must be present at the same time in order to There are many different ways Class A fires can be produce fire: caused and prevented on the jobsite. • Enough oxygen to sustain combustion. A. Spark and friction fires can be caused by the • Enough heat to reach ignition temperature. sparks created with the friction created from • Some fuel or combustible material. grinding nails or other metal objects. Spark Together, these three things produce a fire. Take away fires can also be caused by improperly aligned any of these items and the fire will be extinguished. equipment. Always be cautious of creating sparks near flammable materials. Fires are classified according to the type of fuel that is burning. If you use the wrong type of extinguisher on B. Spontaneous combustion can occur due to the wrong class of fire, you might make matters worse. wood dust igniting in the dust-collection bag, It is important to understand the five different fire (or vacuum, or container. Wood dust must reach fuel) classifications. a temperature of 400 F° or 204 C° for it to ignite. Always remove dust receptacles and dust
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collection systems from the jobsite at the end 6. Select the appropriate type of fire extinguisher. of every day and dispose of them in a proper 7. Identify a safe evacuation route, and don’t let manner. The most-common type of spontaneous the fire block your escape. combustion in our industry is caused by stain 8. P.A.S.S. Method: rags that are not disposed of properly. Oil- based stains, natural oils, varnishes, shellacs, polyurethanes, and paint thinners are common products that can be culprits. Spontaneous combustion occurs when the solvent or substance begins to oxidize. This process causes an exothermic reaction, meaning it releases heat. If the heat has no way to escape, like in a pile of rags, the temperature will continue to rise to a level high enough to ignite the rags. A cotton rag containing any amount of stain residue has the perfect surface-area-to-mass ratio to spontaneously combust. Therefore, you should dispose of rags in an air-tight metal container.
Class B Fires Class B fires are caused by flammable liquids and their vapors. On a wood flooring jobsite, these can include things like lacquer thinner, mineral spirits, solvent- based sealers, and some solvent-based adhesives. You can minimize the risk of Class B fires by turning off pilot lights and all ignition sources before using flammable 9. Back Away. liquids on the jobsite. 10. Evacuate.
Class C Fires Class C electrical fires are caused by faulty cords, loose PART III connections, breaker box fires, bad switches, faulty Electrical Safety equipment, or improper cord selection. Electrical hazards can be found on nearly every jobsite. Whether the hazard is posed by damaged or Fire Extinguisher worn power tools or cords, improperly grounded tools, A. Always have two extinguishers on hand: or the power sources themselves, it is critical to one in the truck and one on the jobsite. understand the potential electrical dangers on the B. Kno w how to operate. jobsite. Most wood flooring professionals are not licensed electricians. However, you should have a clear C. Hold flat and level. understanding of electricity and the requirements your D. Check for and maintain expiration dates. equipment needs to operate properly. You must be E. No smoking. thoroughly cognizant of electrical safety to maintain a safe work environment. F. R esponding to a Fire: 1. Sound the fire alarm. Equipment Requirements 2. Call the fire department. Probably the most overlooked electrical safety 3. Assist any persons in immediate danger to precaution is knowing what the power requirements safety. are for each piece of equipment on the jobsite. It is 4. Before deciding to fight a fire, check the essential to read the operations manual for all following: equipment and understand what the electrical a. Is the fire spreading rapidly beyond the requirements are for each power tool. point where it started? b. If the fire is already spreading quickly, it is best to evacuate the building. 5. Do not fight the fire if: a. You don’t have adequate or appropriate equipment. b. You might inhale toxic smoke. c. Your instincts tell you not to.
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Circuit Breaker Panels The circuit breaker panel should be the first electrical item assessed on the jobsite. Read the owner’s manual on the tools being used on the jobsite to determine power requirements. You should be able to determine whether proper power is available for the equipment you will be using Voltage on the job. If after A multimeter, also known as a VOM (Volt-Ohm- evaluating the Milliammeter), typically measures voltage, current, circuit breaker and resistance. Always keep a multimeter on hand to panel you are still test for proper voltage at power sources and through unsure of power cords. Ensure power at the jobsite is sufficient for the capabilities, equipment being used. If insufficient power is detected, a licensed the use of a power booster can help deliver adequate electrician will need to set up electrical connections. power to the tools being used. The following are some of the basics: A. Neutral and hot wires: Current flows from the Outlets panel toward the load along the hot wires and You should know the basics of the different types of returns along the neutral. Each hot wire’s copper power available at any jobsite. In the United States, tip ultimately connects to its control switch at the 15- or 20-amp breakers are common. These are all- circuit breaker, and each neutral connects to a purpose power sources that run lighting and outlets. common terminal. 30-, 40-, and 50-amp breakers are common power B. Main breaker: This is the on/off switch to the sources for electric dryers, electric ranges, or other entire breaker panel. A 200-amp breaker is large appliances. The type of plug in the wall will be common for a home of 2,000 square feet. dictated by its use. Have adapters made before arriving Smaller buildings may use 150-amp or 100-amp; at the jobsite to be able to connect to each type of small homes and subpanels can use as little as outlet. Also, ensure you take into account the type of 50-amp. power you are attempting to plug into in relation to the C. Double-pole breaker: Uses the entire 240 volts equipment you will be using. Note that power sources available to the panel. The 15-amp breakers often and requirements will differ in other countries. handle baseboard heaters, 30-amp serve water heaters and electric dryers, 40-and 50-amp are Cords for electric ranges, and the 70-amp could serve a The quality of large air conditioner or a subpanel. cords can be easily D. Single-pole breaker: The 15-amp and 20-amp are overlooked, but all-purpose breakers, running everything from can cause serious lights and outlets to the garage-door openers. repercussions if not E. 15-amp AFI breaker: Arc-fault-circuit-interrupter addressed. breakers can prevent fires caused by accidental A. Check cords electrical discharge. regularly for damage or deterioration. If they are F. Ground wires: Grounding prevents a conductor cut, cracked, or have broken insulation, do not not meant to carry current (such as the metal use them. Check and tighten connections on the side of a clothes dryer) from causing injury if plugs and connectors regularly. it’s energized by a frayed hot wire. In a properly B. There are safety regulations you must follow grounded system, appliances and metal boxes on the jobsite related to extension cords. connect back to the grounding bus of the breaker Occupational Safety and Health Administration panel. From there, the system is grounded to the (OSHA) requires three-wire extension cords at earth via buried ground rods. all jobsites. These 3-wire extension cords are designed for hard or extra-hard usage. C. Ground-fault circuit interrupters, referred to as GFCIs, must be used on all projects for 120-volt,
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single phase 15-, and 20-amp services. When PART IV using a generator or temporary pole, a GFCI is required, or a portable unit must be used. Tool Safety D. When the grounding pin on a plug of a power • Start with a safe work area. Keep the work area tool is missing, repair or replace it before using clean and well lit. Cluttered workspaces and the cord. Using a tool with a missing grounding improperly lit jobsites invite accidents. pin can be extremely dangerous for the user. • Do not operate any power tools in explosive If a short were to develop in the tool, the user atmospheres, near flammable liquids, gases or can become the ground in the system, and the dust. Power tools can create sparks, which may electricity may travel through him or her. ignite the dust of fumes. E. Wire gauge is a measurement of how large a • Keep bystanders, children, homeowners, and wire is, either in diameter or a cross-sectional visitors away when using power tools. area. This determines the amount of electric • Grounded tools must be plugged into a properly current a wire or extension cord can carry safely grounded installed outlet. Never remove or cut as well as the electrical resistance and weight off the grounding prong or modify the plug in per unit per length. any way. F. American Wire Gauge (AWG) is a US standard • Store battery packs away from other metal set for non-ferrous (copper or aluminum) objects like paper clips, coins, keys, screws, or wire conductor sizes. The “gauge” means the other small metal objects. These items can make diameter. a connection from one terminal to the other, shorting the battery terminals together and G. Extension Cord Amp Ratings: potentially causing burns or fire. LENGTH IN FEET 16 AWG 14 AWG 12 AWG 10 AWG • Do not abuse or modify the cord of the tool. 25 13A 15A 15A 30A Replace damaged cords immediately. • Always hold the tool by the insulated gripping 50 13A 15A 15A 20A surfaces. Contact with hidden wiring or its own 100 10A 15A 15A 20A cord will make exposed metal parts of the tool “live” and could shock the operator. H. Select the proper gauge cords for the machinery • T he wire gauge and length of any extension cord you will be using. Longer distances will require must be able to handle the amps of the tool. Find heavier gauge cords and/or use of a booster. the amps (A) on the tool’s nameplate and use the When improper gauge cords are used, plugs, chart to determine the necessary wire gauge for wires, and equipment motors can overheat, your extension cord length. causing permanent damage. The size of the wire • Always read and understand the tool’s operator’s in an extension cord set must be sufficient to manual, tool markings, and the instructions handle the amperage that will be drawn by the packaged with the accessory before starting tools connected. any work. • Stay alert and watch what you are doing when Cord Placement using power tools. • Do not use drugs, alcohol, or medication while Never place any cord operating power tools. around your neck or over your shoulders. • Wear clothing that does not have strings or It is unsafe, and if the other fabric or design details hanging that could cord had a nick or cut potentially get caught in a machine. This could in the insulation, it cause serious injuries and is easy to overlook. could get wet from sweat and short out. It also can • Contain long hair when operating power tools. cause body fatigue and muscle fatigue. Our body is • When not in use, tools should be stored in a dry a DC current, and the power source is an AC current, place. meaning it will interrupt the flow of current in our • Electric tools should not be used in damp or wet body. This causes muscle fatigue. locations. • Keep handles dry, clean, and free of oil and Disconnect grease. It is important to disconnect all power when leaving • Be certain the power tool’s switch is off before the jobsite. The cord itself should never be pulled to plugging it in or inserting a battery pack. Do not disconnect it from the power source; instead, remove carry tools with your finger on the switch. it by the plug. • R emove adjusting keys and wrenches before turning the tools on.
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• Unplug tool/remove battery before changing accessories. • Keep hands away from moving/rotating parts. • Only use tools and accessories for the jobs for which they were designed. • Alw ays keep a firm footing when using power tools. Be sure you have balance and control before starting the job. • S ecure and support the workpiece. Use clamps and a stable surface. • K eep guards in place and working properly. • Do not force the tool. • Us e only accessories for the tool recommended by the tool manufacturer. • Use dust collection systems whenever possible. • Do not use the tool if the switch does not turn it 1. When inhaled over long periods of time, on and off. asbestos exposure can result in serious and sometimes fatal conditions. These can include • Inspect the tool before using it. asbestosis, mesothelioma, and lung cancer. • T ools should be serviced by a qualified repair As a result, asbestos is no longer approved center. Only use authorized parts for any repairs as a modern-day construction material. to the tool. 2. Asbestos may be present in many older • K eep the tool clean. Clean and lubricate the tool existing homes and structures. Homes or only as directed in the operator’s manual. structures built prior to 1986 undergoing • Main tain labels and nameplates. renovations should be tested for asbestos. • Only use sharp blades/accessories on the tools. 3. Wood flooring professionals can potentially be affected by asbestos in any remodeling project. If the work is being done in a home or PART V other structure built prior to 1986, you need to be aware of any materials that may contain Industry Regulations asbestos, and laws that could impact you. Specific legislation varies from region to region; 4. Many states have their own laws regarding be sure you understand the requirements for the asbestos removal, and it is your responsibility country, state, county, or the city in which you are to know the laws that are applicable for the working. Regulations may impact your required area in which you are working. You can find working procedures or worker safety, record-keeping, the contact information for asbestos purchasing plans, material disposal requirements, or programs in your area at www.epa.gov/ other areas of your business. In particular, make sure asbestos/state-asbestos-contacts. you understand the current regulatory requirements regarding asbestos, lead, formaldehyde, and silica. Being unaware of these laws, or misinformed about how they affect you, can result in fines. The following is a simplified overview to familiarize professionals with the language used and general concepts of several US federal regulations and is not intended as a complete guide to your legal responsibilities. Persons seeking legal advice on compliance with any other law, regulation, or compliance requirement/claim should consult with the regulatory agency directly and/or a qualified legal professional. A. Asbestos is a naturally occurring silicate mineral that has not been in use in construction for several decades, but can be an issue in older structures. It is composed of thin, fibrous B. Lead has not been in used in construction for crystals that can be released through abrasion, several decades, but can be a concern in older like sanding, and other processes. structures during any renovation project. 1. Lead is a naturally occurring chemical element that was used often in many construction products until the late 1970s.
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2. Lead-based paint may be found on any surface in the home, both inside and outside. When it is disturbed during renovation, repair, or painting activities, dangerous amounts of lead dust can be created and released into the home or building. 3. Because it can be dangerous, the United States Environmental Protection Agency requires that when renovating, repairing, or painting homes built prior to 1978, they must be tested for lead. This requirement also applies to any non-residential building that primarily serves children, like a 2. At the time of publication, both CARB P2 and school or day care. TSCA Title VI directly regulate emissions from 4. Wood flooring contractors have to be four products (plywood, particleboard, MDF, concerned with two specific areas in homes and thin MDF) and indirectly regulate items and other structures built prior to 1978: produced with those products. Both a. If more than 6 square feet of any painted regulations require these composite wood surface is disturbed (including panels meet specified emissions performance baseboards), you must test for lead. standards, regardless of what resins are used b. If you are unsure what type of finish is in their production process. on the floors, you must test for lead. This 3. All mills producing directly regulated is because some wood floor finishes products are required to have a TPC (Third produced prior to 1978 contained lead. Party Certifier) confirm that their production 5. It is critical that testing take place before any procedures will lead to the required results. work begins. Before you conduct any testing, 4. At the time of publication, engineered your company must be certified to do so by flooring produced with plywood or MDF cores the United States Environmental Protection is covered under TSCA/CARB, as is laminate Agency (EPA). This can be accomplished by flooring; however engineered flooring with a following the requirements set forth by the lumber-core is not regulated. EPA related specifically to the Lead Safety 5. Both regulations place a documentary Renovation, Repair and Painting Certification burden on all parties in the supply chain to program. You can get more information track impacted material and require buyers about the program at www.epa.gov/lead/ to exercise reasonable prudent precautions renovation-repair-and-painting-program. to ensure compliance. There are some 6. If after testing is completed lead is found differences between the rules, which to be present, you then must implement generally will impact only manufacturers, but lead-safe work practices. To accomplish this, companies selling into the state of California both your company, and the individual doing should ensure that they are meeting CARB’s the work, must be trained by the EPA. unique requirements as well as TSCA Title VI. 7. Compliance with this law is mandatory Some specific documentary burdens include: nationwide. Fines can be severe, and can a. Impacted flooring sold in the United range into the hundreds of thousands of States must be labeled to indicate it is dollars per violation. TSCA Title VI compliant for formaldehyde emissions. All labels must include, at a C. Formaldehyde : The U.S., as well as some minimum, a statement of compliance, a individual states and other countries, have strict production date, and a name of the laws regarding formaldehyde emissions from manufacturer or other responsible party. composite wood products. See resources at the end of this section that will help you understand b. A compliance statement must appear in detail your responsibilities based on your role on transactional paperwork between in the supply chain. businesses. The final rule allows for flexibility for panel producers, 1. The state of California was the first to fabricators, importers, or distributors significantly regulate formaldehyde emissions to choose the document on which to from composite wood products, and the include the compliance statement. program, which the industry refers to as They may affix the statement to a bill of “CARB,” was the basis for the federal lading, invoice, or comparable document; government’s program, known as “TSCA all documents; or any combination Title VI,” now in effect.
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thereof. A statement of compliance is not required on invoices to final consumers. c. EPA requires records of production, purchases, and sales to be kept for three years, and made available to EPA upon request. 6. Some mills will use the term “NAF Exempt” or “ULEF Exempt” instead of Certified. This means that they have demonstrated to their TPC that they are using “No Added Formaldehyde” glue and regularly meet a lower emission level than required, or they are making material that is “Ultra Low- Emitting Formaldehyde,” which also means they regularly meet a lower emission level a. Under OSHA rules, silica exposure levels than required. Therefore, they are designated are limited to 50 micrograms per cubic “exempt” from the quarterly testing by a TPC meter of air per eight-hours. To meet that is required for the regularly certified these requirements, floor grinders must mills. It does not mean they are exempt from be used according to manufacturer the regulation itself. recommendations in order to minimize 7. All parties in the supply chain should dust emissions. understand their responsibilities under these b. Dust collection systems must provide air regulations. For more information: www.epa. flow as recommended by the gov/formaldehyde/formaldehyde-emission- manufacturer, and have a filter with standards-composite-wood-products. ≥99% efficiency, as well as a filter- D. Crystalline silica is a common mineral that is cleaning mechanism. a natural part of the Earth’s crust. It is found c. In enclosed areas, exhaust systems must in materials like soil, sand, and stone. It is used be used to minimize dust accumulation, to produce many man-made materials such as and a HEPA-filtered vacuum must be concrete and bricks. used to remove loose dust in between 1. Inhaling silica dust can be harmful to humans. each pass. Dry sweeping and the use of These particles are very small, about 100 compressed air to remove silica dust times smaller than a grain of sand, so they should be avoided. are not visible to the naked eye. Short-term 3. In addition, employers must: exposure poses little to no risk, but long-term a. Establish and implement a written exposure can result in serious illness, exposure control plan. including silicosis, lung cancer, chronic b. Designate someone to monitor the plan. obstructive pulmonary disease (COPD), and kidney disease. c. Restrict practices that increase exposure. 2. Occupational Safety and Health Administration d. Offer medical exams for exposed (OSHA) has issued a respirable crystalline silica employees. standard for construction. In the wood e. Train workers to identify and limit flooring industry, the most common source of exposure. silica dust is from grinding concrete to level a f. Maintain records for exposure, medical concrete subfloor, mixing self-levelers and exams, and other related data. patches to flatten a subfloor, and existing 4. Failure to comply with the regulation can demolition in preparation for wood floor result in significant fines ranging into the installation. tens of thousands of dollars. More detailed information about the Respirable Crystalline Silica Standard for Construction is available from OSHA at www.osha.gov/Publications/ OSHA3902.pdf.
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PART II Power Tools There are several types of power tools, based on the power source they use. A power tool is a tool powered by electricity, battery, compressed air, or fuel. Power tools also are classified as either portable or stationary. Appropriate personal protective equipment should be worn due to hazards that may be encountered while using power tools. Wood flooring professionals should be trained in the proper use of all tools and should understand the potential hazards and the safety precautions of each tool. The following are some of the more common power tools used in the wood flooring PART I industry along with some of the options each has to offer. Hand Tools Hand tools are non-powered. They include anything from hammers to squares. The greatest hazard posed Dust Collection System by hand tools results from misuse and improper A. WHAT IS IT: A dust collection system is an air maintenance. Appropriate personal protective quality improvement system used in industrial, equipment should be worn due to hazards that may commercial, and be encountered while using hand tools. Common hand home production tools used in the wood flooring industry include: shops to improve • Moisture meters breathable air • Thermo-hygrometers quality and safety by removing • Batteries particulate matter • Tape measures from the air and • Chalk line the environment. • Pencil/pen Each tool should • Squares & straight edges have a collection • Laser level/string-line point where you can attach a • Utility knife collector hose. • Prybar B. TOOL OPTIONS: • Wall-jacks There are many • Straps and clamps different types of • Chisels dust containment • Nail sets systems available. • Hammer/flooring mallets These systems • Nail pullers range in size and capacity. Be sure to completely understand • Screw drivers the maintenance of the dust collection system • Trammel points as well as its capabilities and limitations when • Scrapers & files connecting to any power tool. Some installations • Surfacing block plane and jobsites may require use of HEPA or similar • Trowels regulatory dust containment. Collecting dust • Extension cords from the tools results in a cleaner jobsite and safer environment. • Tapping blocks • Pliers and wrenches
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Miter Saws Table Saws A. WHAT IS IT: A miter saw sits on a fixed base, with A. WHAT IS IT: The table saw consists of a circular a blade mounted to an arm that can be pivoted saw blade, mounted on an arbor that is driven from 0 degrees to -45 or +45 degrees. As the by an electric motor (directly, by belt, or by name suggests, these saws cut through the gears). The blade protrudes upward through the work piece at a set miter angle. They are used surface of a table, which provides support for for crosscutting, mitering, or beveling wood, the material being cut. They are commonly used nonferrous metals, and plastics. for crosscutting, ripping, and other straight cuts, B. T OOL OPTIONS: There are three general types as well as for dadoing and molding. of miter saws: standard miter saws, compound B. TOOL OPTIONS: There are two basic types of miter saws, and sliding compound miter saws. saws: portable and stationary. It is important It is important to understand the capabilities of to understand the capabilities of each type, to each type, to determine which is most suitable determine which is most suitable for your needs. for your needs. 1. Portable Table Saws: There are three 1. S tandard Miter Saw: This is the simplest general types of portable table saws. Because version of a miter saw. It is any wood cutting they are designed to be portable, they are saw with a blade on an arm, mounted to a normally smaller and lighter weight. base, and capable of making between -45 and a. Bench-top Saws: smaller rip capacity and +45 degree cross-cut angled cuts. table, with no stand or transport wheels. 2. Compound Miter Saw: This saw is capable of b. Compact Saws: may include features such cutting both a bevel and miter. A compound as stands, or surfaces made of cast iron. miter saw adds the ability to make bevel cuts c. Jobsite Saws: heavier duty components from 0 to +45 degrees in addition to its that can produce more accurate results, mitering ability. There are two types of and often larger rip capacity. compound miter saws: single bevel or double 2. Stationary Table Saw: There are three basic bevel options. A single bevel will only tilt in types of stationary table saws. Compared to one direction, while a double bevel can go portable saws, they are much larger and either left or right. heavier, more accurate, and more powerful. 3. Sliding Compound Miter Saw: This saw is a They are not really portable, although they type of miter saw that adds rails to let the can be mounted to a mobile base for saw blade slide front to back across the wood. transportation around the workshop. It gives you a much greater cutting capacity a. Contractor Saws: a cheaper alternative than the same size miter saw without rails. to a full-size cabinet saw that may weigh There are two types of sliding compound as much as 200-300 lbs. They are much miter saws: single bevel or double bevel more powerful than a portable saw. options. A single bevel will only tilt in one direction, while a double bevel can go either b. Cabinet Saws: Cabinet saws are extremely left or right. precise, heavy, bulky, and made to last for decades. Each component of a cabinet saw is designed to be durable and robust, and to withstand heavy-duty use. c. Hybrid Saws: Hybrid table saws offer some of the advantages of cabinet saws at a lower price than traditional cabinet saws. Hybrid saws offer an enclosed cabinet to help improve dust collection. The cabinet can either be similar to a cabinet saw with a full enclosure from the table top to the floor or a shorter cabinet on legs.
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Band Saws to cut masonry, plastics, or metal. The most common-size blade used for cutting wood and A. WHAT IS IT: The framing is 7¼” designed for crosscuts or rips in band saw is a saw various wood and synthetic rigid materials. with a long blade that consists of a B. T OOL OPTIONS: Circular saws are available in continuous band of many styles: flexible steel with 1. Sidewinder/In-Line Circular Saws: This is the saw teeth, stretched most-common type of circular saw used. The between two or motor is normally mounted on the side of the more idler wheels. blade, making it a compact tool. The blade Band saws cut fast rotation speed is either 1,725 or 3,450 RPM, and accurately due based on the motor direct-drive rotation speed. to continuous tooth 2. Worm Drive and Hypoid Circular Saws: The blade action and a motor is mounted toward the back of the tool, slow-moving blade, making it significantly longer and heavier which allows for more finesse and control. The than a sidewinder. The gears of these saws blade comes down from an upper wheel, through are what differentiate them from each other, a bearing/saw guide yoke and into an opening in but provide more torque than a sidewinder. the table to a lower wheel. The table is where the The blade rotation speed is normally about workpiece is moved into the moving saw blade 4,500 RPM. The blade is normally positioned to create cuts. While the blade is continuously to the left side of the motor. moving, only a small part of it should be exposed by adjusting the elevation of the guide post, Plunge-Cut Saw/ which holds a blade guard above the cutting area. Track Saw B. T OOL OPTIONS: In general there are three types A. WHAT IS IT: A plunge- of band saws used with flooring installations: floor cut saw has a blade that standing, benchtop, and portable. It is important spins and cuts similarly to understand the capabilities of each type, to to a circular saw, but determine which is most suitable for your needs. with a fixed guard, 1. Floor Standing: powerful saws with a larger which provides superior workspace, table size, and positioning dust collection and capabilities, for use when making more- safety features. The saw intricate cuts or ripping larger boards. moves in a metal track along a straight line. When 2. Benchtop: Benchtop band saws are more- you want to cut, simply attach the metal track on mobile versions of floor standing models. to the workpiece, place the saw on the track, then 3. P ortable: Portable band saws are about the plunge the saw into the work-piece and move it size of a handheld circular saw and are forward along the guide (or the track). mostly used for jobsite work, often trimming B. T OOL OPTIONS: Many plunge-saws have variable excessive pieces off. speeds, which allow for cutting through a variety of materials. The track comes in many length options. These saws are designed for plunging into a material, and most have a depth setting for precision cuts.
Oscillating Saw (Multi-Tool) A. WHAT IS IT: An oscillating saw is a compact, corded or cordless, portable power tool that accepts a wide range of interchangeable blades. Circular Saws Because of the tool’s A. WHAT IS IT: A circular saw consists of a motor, short range of blade blade, blade guard, and a base. It is a power motion, small front-end tool that cuts materials using a round-toothed profile, and blades that or abrasive blade. They are available in corded extend past the snout or cordless options. Most circular saws used in of the tool, it reaches the wood flooring industry are hand-held types, in to places other and are specifically used to cut wood. These power tools can’t, including narrow spaces, tight saws may also be equipped with blades designed corners, and awkward angles.
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B. T OOL OPTIONS: Most oscillating saws offer Scroll Saw variable speeds. The blade vibrates— or oscillates— A. WHAT IS IT: back and forth at very high speed (from 11,000- A scroll saw 21,000 oscillations per minute). This tool is often is a small called a multi-tool due to the wide variety of electric or tasks it can perform, including cutting, scraping, pedal-operated rasping, sanding, polishing, and grinding. reciprocating saw used to cut Reciprocating Saw fine, intricate A. WHAT IS IT: A type of saw in which the cutting profiles and patterns. The fineness of its blade action is achieved allows it to cut more delicately than a jigsaw. through a Scroll saws come with a variable speed control to “push and pull” modulate the rate of cut through materials and reciprocating for adjusting to various blade-cutting capabilities. motion of the B. T OOL OPTIONS: The throat size determines the blade. It is size of the workpiece capable of being cut. Throat generally used in size can vary from 12” to 30” or more. Most demolition work. scrolls saws offer a small light on a flexible arm B. TOOL OPTIONS: These saws may be used to that illuminates the work area and a dust blower cut metal, pipes, wood, nail-imbedded wood, nozzle to keep the work space clear while working. and other materials dependent upon the blade being used. Many reciprocating saws also have an orbital action setting, which moves the blade in a slightly circular motion as it moves in and out of the tool. This allows faster cuts in softer materials and facilitates faster chip removal from the blade path.
Jigsaw (Saber Saw) A. WHAT IS IT: A jigsaw is a saw that uses a reciprocating blade to cut straight lines or irregular curves in wood. It will Router also make interior A. WHAT IS IT: A machine with a revolving vertical cuts, or cuts within spindle and cutter for milling out the surface of a board without wood. Routers are used as a “hand-shaper” to cutting through create profiles, decorative cuts, shaping, making the work from an joints, and trimming wood. outside edge. B. TOOL OPTIONS: Most routers have a variable B. T OOL OPTIONS: Most jigsaws come with variable speed option to adjust based on the material speed options, which allow for adjustment based being cut. Routers normally have either a ¼” or on the material being cut. Most blades cut on ½” collet, which will determine the bit used with the upstroke, which is good when used for rough the tool. Routers can be divided into two general cutting. Reverse-tooth blades have downward groups: fixed-base and plunge-base routers. facing teeth, which produce clean cuts on the 1. Fix ed-Base Routers are locked at a fixed face of the board. These saws also have an location in the base, and the cutting bit adjustable base that allows for beveled cuts to cannot move, or plunge, from top to bottom. be made through the wood. These routers are commonly used as router tables, where they are mounted underneath a stationary table. 2. Plunge-Base Routers move up and down on the base, which has spring-loaded arms on either side that allow the user to manually “plunge” the cutting bit down into the material from above.
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Drill/Driver B. TOOL OPTIONS: A. WHAT IS IT: 1. Handheld A hand-held Grinder tool that attachments has a chuck include cut-off (keyed or discs, abrasive keyless) used grinding discs, to hold bits in sanding discs, place for drilling, driving, or hammering. wire brush wheels, grinding stones, and polishing pads. B. TOOL OPTIONS: There are many types of drills Attachments are normally available in 4”, and drivers, but for the purposes of the wood 4.5”, 5”, 6”, 7”, 9”, and 12” sizes. flooring industry, we will focus on these general 2. Bench Grinders categories: drills, impact drivers, hammer drills/ are mounted to a rotary hammers, and drill presses. bench or 1. Drills are used to create a hole with a rotating pedestal, and drill bit into a material. Drills are rated by the used specifically maximum capacity of their chuck. to drive abrasive 2. Impact Drivers wheels. They have a rotary impulse normally are mechanism that used for allows the tool to sharpening cutting tools, cleaning or polishing drive fasteners into workpieces, or for rough shaping metal pieces. a material. 3. Hammer Drills/ Guillotine-Style Shear Cutter Rotary Hammers use an impacting/ A. WHAT IS IT: A hammering action in non-powered, combination with, or compact without, rotation. These drills use specially guillotine-style designed bits to drill holes into masonry cutting tool materials or for demolition. designed to cut through thin-profile engineered wood flooring as well as other types of flooring materials. These cutters have a long handle that provides the leverage necessary to cut through different types of flooring. B. TOOL OPTIONS: These cutters are available in different sizes to accommodate different types of flooring. Due to the nature of how these cutters work, there is no power necessary to operate the 4. Drill Press is a mounted tool, and no dust produced during operation. style of drill that includes a base, column (or pillar), Floor Roller adjustable table, spindle, A. WHAT IS IT: A non- chuck, and drill head. marking, segmented roller, required with some Grinder adhesives, that exerts (Handheld and Bench) even pressure on a glued- A. WHAT IS IT: Grinders are highly down wood floor, cork, or versatile tools capable of accepting a variety underlayment, ensuring of attachments and accessories that allow the that the adhesive is tool to be used for cutting, grinding, sanding, transferred to the back polishing, sharpening, or wire brushing. of the installed floor. B. T OOL OPTIONS: Floor rollers are available in different sizes and different weights. The weight is determined by the adhesive manufacturer.
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PART III 2. Fittings: Hose connections should be designed for the pressure and service Pneumatic Tools indicated on the tool. All connectors and Pneumatic tools are powered by compressed air. couplers should be compatible with and designed for the hose and tool being used. Air Compressors Flooring Nailers A. WHAT IS IT: Air compressors are A. WHAT IS IT: A type of tool used to drive flooring tools that convert nails or staples into wood flooring. power into stored B. TOOL OPTIONS: energy in the form of compressed air. B. TOOL OPTIONS: 1. Tank Capacity (gallons): For small jobs like installing trim or flooring repairs, the pneumatic guns can operate on the air supplied by a relatively small tank. For most wood floor installations, more air is required to be delivered to the constant demand of a flooring nailer. When more than one gun is being used on one 1. Malle t-Actuated Nailers/Staplers: Flooring compressor, a larger tank will also be nailers are mallet-actuated nailers capable of required. The larger the tank, the longer the driving staples or flooring cleats/nails into job can be done at the required PSI before the tongue of a piece of wood flooring. Each the compressor needs to rebuild pressure in model has different capabilities and the tank. magazine cartridges for use with specifically 2. Oil or Oil-free: Oil-free designs are most designated fasteners. common and require less maintenance. 3. S CFM: Standard Cubic Feet per Minute (SCFM) is a measure of air (under standardized conditions) being delivered by the compressor to the air tool. Compressors with a higher SCFM rating provide more air. SCFM requirements should be dictated by the tools being used. 4. P SI: Pounds per square inch is the measure of air-force delivered by the compressor. For one flooring nailer to operate, the compressor should be able to continuously deliver 80-110 PSI at 3½” cubic feet of air per minute. 2. Trigger-Activated Nailers/Staplers are engaged by a trigger and capable of driving the flooring fastener into the tongue of a piece Hoses of wood flooring. Each model has different A. WHAT IS IT: capabilities and magazine cartridges for use Compressor air with specifically designated fasteners. hoses are used 3. Manual Nailers are not powered using for conducting compressed air, but rather plunger-driven by compressed air to blunt force. These may be available as the tool. multi-hit or B. TOOL OPTIONS: ratcheting 1. Hose size is measured by its inner diameter. mechanism Most pneumatic nailer manufacturers to allow the recommend the use of a minimum user to 3/8”diameter hose supply connectors and a strike 50’ or smaller hose. multiple times.
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Pneumatic Nailers PART IV A. WHAT IS IT: A type of tool used to drive nails into wood or some other kind of material. Blades and Bits B. TOOL OPTIONS: Circular Saw Blades 1. Finish Nailers: A. Blades used for Available as miter saws, table pneumatic or saws, circular saws, electric. and radial arm saws. These nailers B. Saw teeth may be drive 14g to made of steel or 16g nails, carbide. upwards of C. The cutting edge of 2½” in length. each tooth is ground to a specific profile, which They normally are used where flooring nailers controls how it cuts. Flat teeth shave the wood cannot be used. fibers like a plane, beveled teeth cut them in 2. Brad Nailers: Available as pneumatic or two like a knife, and triple-chip teeth are mixed electric. These nailers drive 18g brads, with flat teeth to cut tough materials. The mix of upwards of 2” in length, leaving smaller holes teeth on a blade is known as the grind. in the surface D. Ripping blades are used for cutting parallel to of the board. wood grain, ripping to width. These blades have They normally a large hook angle (20-25 degrees). These blades are used have fewer teeth and wide gullets, and are most where commonly used with table saws. flooring nailers E. Crosscut blades are used for cutting across the cannot be wood grain, cutting to length. These blades have used, or for a small hook angle (5-10 degrees). These blades temporary have more teeth and narrow gullets, and are hold power while adhesive sets up. more commonly used with miter saws. 3. Pin Nailers: This is the smallest nailer in the F. Combination blades are used for ripping and trim-nailer family. These nailers normally drive crosscutting wood. These blades have teeth 23g, headless nails, upwards of 2” in length. arranged in sets of five – first a ripping tooth These fasteners leave a very small hole in the preceded by a wide gullet, then four crosscut surface of teeth with narrow gullets. The hook varies the board, between 5-25 degrees, depending on the tooth. oftentimes These are commonly used with circular saws, and not needing miter saws. to be filled. G. Plywood blades are used for cutting plywood. They normally They are designed to make smooth cuts. These are used for blades have small hook angles (5-10 degrees) temporary with narrow gullets. For cutting hardwood veneer hold power plywood, the blades normally have 80 or more while small teeth, whereas when cutting OSB or other adhesives substrate plywoods, a more-aggressive blade set up, or configuration can be used, such as 24 tooth for delicate blades. trim work. H. Hollow ground planer blades normally are used for sawing operations requiring a smoother cut. They have the same hook angle and tooth arrangement as combination blades, but the teeth have no set, and are only available in steel (not carbide). I. Thin-kerf blades are used for ripping or crosscutting hardwood. They are available in rip, crosscut, and combination configurations, and are carbide-tipped only. The plate and teeth are approximately 2/3 the width of ordinary blades.
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Bandsaw D. Metal-cutting blades for work in metals Blades (standard tooth). A. Standard- E. Spiral blades for omnidirectional cuts in wood tooth blades and soft metals (standard tooth). are best used for crosscutting, joinery cuts, and smooth surfaces. These also have more teeth per inch and can cut slower and smoother than other blades. B. Skip-tooth blades are best used for cutting curves and contours, or thick stock. The teeth have the same profile as standard blades, but are spaced much further apart. These blades also cut much faster. C. Hook-tooth blades are best used for ripping, resawing, cutting green or resinous wood, or Router Bits thicker stock. The pitch is the same as the A. A router bit consists of a cylindrical shank and skip-tooth blade, but the rake angle is about 10 one or more flutes that cut the work. Bit flutes degrees, which allows for a more-aggressive cut. may be made of steel or carbide. B. Most bits have straight flutes. Bits with shear Jigsaw Blades flutes leave a smoother cut, whereas bits with A. Blades vary in spiral flutes help clear material from plunge cuts. their effective Stagger-tooth and chip-breaker flutes are made cutting length, to cut plywood and particleboard. number of C. Some bits have pilot bearings, either on the top or teeth per inch bottom of the cutter head, to guide the bit along (tpi), and the edge of the work or template. Unpiloted bits manner in may have top-cutting flutes or point-cut flutes which the teeth that allow you to plunge into the wood. are set. D. Although there are hundreds of types of B. General Purpose: 6-8 tpi, used for rough cuts router bits, they can all be organized into in wood. two categories: C. Smooth Cut: 6-8 tpi, used for clean cuts in wood. 1. Gr oove- D. Plywood: 12-14 tpi, used for cutting sheet materials. forming bits, which cut E. Detail: 12-14 tpi, used for cutting more-intricate grooves, patterns. dadoes, F. Laminate: 10-14 tpi, reverse teeth used to cut mortises, and laminated material on the down stroke. recesses in G. Offset: 6-8 tpi, offset blade used for cutting up to the work. a corner. 2. E dge-forming bits, which Scroll Saw cut rabbets, Blades bevels, ogees, and other A. Scroll blades shapes around for heavy-duty the perimeter work in wood of the work. and soft metals (standard tooth). B. Fret blades for fine work in wood and soft metals (includes skip tooth, double-skip tooth, and reverse skip tooth). C. Precision-ground blades for cleaner cuts and better control (includes skip tooth).
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PART I Solid/Engineered A. Solid Wood Wood Flooring Options Flooring Wood is the hard fibrous material that forms from the 1. Solid wood main substance of the trunk or branches and beneath flooring is the bark of a tree. A wood floor is any flooring product exactly what the that contains real wood as the top-most, wearable name implies, a surface of the floor. solid piece of Wood floors come in many different options. These wood from top include, but are not always limited to, the following: to bottom. 2. Solid wood Hardwood/ floors can be Softwood sanded and A. Hardwoods come refinished from deciduous, numerous times during their service life. broad-leaved trees 3. Solid wood floors should not be installed that lose their leaves below grade, which means below ground annually. Hardwood level, unless otherwise recommended by the comes from manufacturer. angiosperm trees. B. Engineered Angiosperm trees Wood Flooring produce enclosed 1. Engineered wood seeds such as pecans, acorns, or walnuts. flooring is real Hardwood trees include oak, maple, ash, cherry, wood flooring as and others. well, but instead B. Softwoods come of a solid piece of from conifers, which wood from top are needle-bearing to bottom, it is and usually remain made using green throughout the several layers of year. Softwood comes wood veneers or from gymnosperm lumber core that are bonded together using trees. Gymnosperm adhesives. trees produce 2. No matter what the thickness of the uncovered seeds, engineered product, it is the top layer that such as pinecones. determines the final appearance of the wood Softwood trees include pine, spruce, Douglas fir, floor. This wear layer will be the species of cedar, and others. wood that is selected. C. It’s important to remember that being hardwood 3. The construction of engineered wood flooring or softwood does not necessarily reflect density. can vary. The construction varies by Some softwoods are harder than hardwoods and manufacturer and by product. some hardwoods are softer than softwoods. 4. The thickness of the finished product can range from 3/8” to 3/4”. Domestic/Imported 5. The top layer of engineered wood flooring A. Domestic woods are wood species grown and typically is referred to as lamina or lamella. harvested within the United States and Canada. Each layer is bonded to adjoining layers using adhesive. B. Imported woods (also known as exotic or tropical species) are wood species grown and 6. The middle layers, which are called core layers, harvested outside the United States and Canada. can be made of the same species as the wear layer, or an entirely different species. The bottom layer is called the backing. 7. In general, due to its’ construction, engineered wood flooring can be installed above- on- or below-grade.
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C. Engineered Composite Wood Flooring A. Plains awn/Flatsawn: Wood cut parallel to the 1. Engineered composite wood flooring uses real growth rings so that the growth rings are mostly wood on the wearable surface that is bonded parallel (0° to 45°) to the wide face of the board to a multitude (a tangential cut) is called plainsawn in hardwoods, of composite and flatsawn in softwoods. Plainsawn flooring is platform more dimensionally stable in thickness (radially) materials and less stable in width (tangentially). using adhesives. 2. In general, due to its construction, engineered composite wood flooring can be installed above- on- or below-grade. B. Riftsawn/Bastard-Sawn: Wood cut neither parallel nor perpendicular to the growth rings Jobsite-Finished/Factory-Finished so that the growth rings make angles of 30° to 60° to the face of the board is called riftsawn in A. Jobsite-finished floors are manufactured and hardwoods, and bastard-sawn in softwoods. installed in a raw state and sanded and finished on-site. B. F actory-finished floors are just as the name implies. The flooring has finish applied at the factory prior to installation.
C. Quartersawn/Vertical-Grain: Wood cut perpendicular to the growth rings so that the growth rings are mostly perpendicular (45° to 90°) to the wide face of the board (a radial cut) is called quartersawn in hardwoods, and vertical- grain in softwoods. Quartersawn lumber is more dimensionally stable in width (radially) and less stable in thickness (tangentially).
Strip/Plank/Wide Plank/Parquet A. Strip wood flooring is manufactured in linear widths less than 3”. B. Plank wood flooring is manufactured in linear D. Livesawn: Wood cut from the outside diameter widths greater than or equal to 3”, and less than through the heartwood incorporating the full or equal to 5”. range of the above characteristics on the face C. Wide plank wood flooring is manufactured in of the board is known as live-sawn material. linear widths greater than 5”. This cut is typically wider and incorporates D. Parquet flooring is any pattern that is geometric all of the dimensional stability and aesthetic in shape as opposed to linear. The traditional characteristics of the other cuts. finger block pattern is a very common and simple parquet pattern, but parquet can vary in style, width, complexity, and pattern.
Saw Cut How wood is cut from the log will affect appearance and performance of wood flooring. There are several sawing methods used for the production of both solid and engineered wood floors.
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E. End-Grain: Wood the National Oak Flooring cut so that the face Manufacturer’s Association, of the floor surface and Wood Flooring exposes the ends of Manufacturer’s Association; the growth rings is currently the wood flooring the transverse cut, mill certification program more often known as administered by the NWFA), end-grain. End-grain or by hardwood flooring manufacturers that flooring will shrink determine their own classifications and create and swell according to their own grades, or “proprietary grades.” the tangential value in the direction across the circumference of the growth rings and according Beveled edges to the radial value in the direction perpendicular to the growth rings, with essentially no A. Beveled edges are a feature of most factory- movement in finished wood floors. A bevel refers to an edge of thickness. a board that is not perpendicular to the face. F. Sawn Veneers: With B. The degree of beveling varies depending on engineered wood the manufacturer flooring, the top and the specific veneer (or lamina) product. Typical is sawn in the same bevel styles include way as normal solid the following: wood flooring, and is • Square edge available in any of the cuts previously mentioned. • Full bevel The only difference is the thickness of the cut, • Micro bevel which varies from product to product. • Pillowed bevel G. Sliced Veneers: With engineered wood flooring, • Chiseled edge the top veneer is sliced from the lumber (called a cant). This process of Antique Reclaimed/Recycled/Salvaged producing veneers has thickness limitations A. Post-Consumer Recycled/Antique Reclaimed and can stress the Wood: Wood or wood fiber that has been wood fibers, but has reclaimed from an end- user after being used very similar natural, for its original intended purpose. End-users physical, and strain may include individuals, characteristics as a households, or industrial sawn veneer. users of the product. H. Rotary-Peeled B. Pre-Consumer Veneers: With Recycled Wood: engineered wood Wood or wood fiber flooring, the top that is created as a by- veneer is produced product of a secondary by positioning full manufacturing process logs onto a large and is not typically lathe, which spins the log against a sharp blade, re-used on-site in the producing a distinct, purely tangential grain- same process that pattern. The grain pattern repeats on larger generated it (also sheets. called post-industrial recycled wood). Grade C. Salvaged Wood: Wood or wood fiber that comes from logs that have been salvaged from the A. Grading is an essential part of doing business following sources: post-agricultural (e.g., fruit in the hardwood floor industry. Grades group and nut orchards); urban forests (street trees); flooring with similar qualities, bringing a degree waterways (sunken of consistency to products from different mills. logs raised from Grades tell the purchaser what to expect when rivers, reservoirs, and buying product, including surface characteristics, lake bottoms); and required lengths, and milling tolerances. other sources that are B. Grades are established through industry mill otherwise not intended certification programs such as NOFMA (formerly to be harvested.
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Other (Non-Wood) Flooring Products PART II A. Cork Flooring Trim and Mouldings 1. While cork Mouldings are used to cover the expansion area, to technically is hide cut ends, to adjust height differences or transitions not considered between floors, and to aesthetically finish the area. a hardwood, it Profiles, species, and availability vary through the does come industry. from a tree. Cork comes from the cork Baseboard oak tree. While Mouldings wood flooring is (Skirting harvested by Board) using the wood of the tree, harvesting cork Baseboard mouldings utilizes the bark of the tree. are used where 2. Cork is a natural product that remains largely the floor and walls unchanged by processing. It is a naturally meet. They form a fire-resistant material that does not release visual foundation any toxic gases during combustion. and are important 3. Cork absorbs ambient sound, which makes it in establishing the an excellent sound insulator. Because it has an character of a room. Traditional baseboard profiles elastic nature and miniature cell composition, measure from 3/8” to 3/4” thick, and vary in height. cork is an extremely durable flooring material. Functionally, they protect the walls from kicks, bumps, Cork resists the growth of mold, mildew, and furniture, and cover perimeter expansion space where bacteria. It also repels bugs and dust mites the floor meets the wall. due to the presence of a naturally occurring substance called suberin. Base Shoe B. Bamboo Flooring (Shoe Moulding) 1. Bamboo is not wood; it is a A narrow moulding grass. It is one that is normally of the fastest used in conjunction growing plants with, or instead in the world. In of, baseboard to fact, some conceal the required shoots have expansion space been observed between the wall, to grow more than three feet in a single day. cabinets, or steps, and the wood flooring. It is flexible Bamboo can regrow itself without replanting, enough to conform to irregular surfaces. Base shoe so it is a highly sustainable resource. profiles normally measure from 3/8” to 5/8” thick, and can vary from 1/2” to 1” in height. It is important when 2. Bamboo is one of the oldest building installing base shoe to avoid nailing it to the flooring. materials known to man. Only nail it to the wall or baseboard. 3. Bamboo flooring comes in three common styles: vertical, horizontal, and strand-woven. Quarter Round Quarter round is, as the name insinuates, one quarter of a full round. It is normally used as an alternative to base shoe to conceal the required expansion space between the wall, cabinets, or steps, and the wood flooring. It is important when installing quarter round to avoid nailing it to the flooring. Only nail it to the wall or baseboard.
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Reducer T- M o u l d i n g Reducers are used T-mouldings are to provide a smooth commonly used to transition between join two areas of floors of uneven flooring that are heights. Reducers the same thickness are often used or to join floating between wood hardwood floors floors and thinner between two rooms, floor coverings in doorways, or such as vinyl or low pile carpet. It also can be used to where the flooring manufacturer requires additional cover expansion space around vertical surfaces such as expansion space based on the floor span. T-moulding fireplace hearths when mounted directly to the surface can also be used to conceal concrete construction of the flooring. Reducer profiles normally measure joints or internal expansion joints left during the from 5/16” to 3/4” thick, and can vary from 1” to more installation. T-moulding should never be fastened to the than 3 1/2” wide. wood flooring. It must only be attached to the subfloor, in order to maintain adequate expansion space. Overlap Reducer Nosing Overlap reducer (Stair Nosing, is typically used Bullnose, in floating floor Landing installation methods. Tread) This multi-purpose Nosing is the moulding is used to horizontal, provide a smooth protruding edge transition between of a stair where floors of different heights, or different types of flooring. most foot traffic Overlap reducer should never be fastened to the wood frequently occurs. flooring. It must be attached only to the subfloor, in The nosing provides a transition from the floor level order to maintain adequate expansion space. to any space below the floor elevation. It starts flush with the flooring and makes a finished edge on the Threshold outer face. They are used to cover the outside corner (Baby of a step, milled to meet the hardwood floor in the Threshold) horizontal plane, or to meet the riser in the vertical plane. Be sure to check with local building codes for Thresholds are stair nosing overhang, rise/run, and proper installation designed for the requirements for stair nosing. transition between floors of different heights, and are Overlap commonly used to Stair Nosing make the transition Overlap stair at doorways, nosing normally between interior is used with rooms, and to the floating floor outside. Threshold installation profiles normally methods, where measure from 5/16” the flooring to 3/4” thick, and meets a step can vary from 1” down or landing. to more than It is used to protect the edges and provide a finished 3 1/2” wide. look. It is different from flush stair nose; overlap step nose has a slightly raised profile that overlaps the flat flooring surface, in order to maintain adequate expansion space. Be sure to check with local building codes for stair nosing overhang, rise/run, and proper installation requirements for stair nosing.
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Stair Tread available in any species, any size, and any The horizontal part of a stair upon which the foot thickness to match different flooring profiles, and is placed. with or without dampers. C. Horizontal Baseboard Registers: A baseboard vent that is installed with the replacement of baseboard mouldings where wall ventilation exists. They are often used to replace the builder-grade metal baseboard vents. These vents are normally available in selected species and at standard wall A. Solid stair treads are pieces of wood that are vent sizes, with or without dampers. used as the actual stair steps themselves or, more commonly, to cover the existing sub treads Custom Mouldings beneath. Mouldings created for unusual circumstances may be B. False tread manufactured to jobsite requirements to complement end caps the wood floor and allow for proper transition and are used to coverage of expansion space. Custom mouldings can be create the custom milled to any shape or size, overlapping or flush, look of steps and out of any material. with solid treads and a carpet runner. In this case, caps are placed at one or both sides of the stair and it is carpeted in between. PART III C. Overlay Packaging stair treads are used A. Factory-finished hardwood flooring is normally specifically packaged in cartons or boxes. to cover B. Unfinished hardwood flooring is usually packaged existing sub treads with less impact on the in bundles. Bundles may be available in two types: height/rise gain in a remodel project. bundled flooring (also referred to as “random- length bundles”) and nested bundles. Stair Riser 1. Bundled flooring consists of flooring pieces The vertical component of a step that range from 6”+/- the nominal length of filling the space between the treads the bundle. A run in bundled flooring is a single piece of flooring. 2. Ne sted bundles consist of flooring that is Floor Vents placed end-to-end continuously in runs, with A. Self-Rimming Vents (Drop-In): A floor vent that the run length equaling the 6”+/- nominal drops into an existing HVAC vent. These vents bundle length. normally overlap the floor on all four sides, and C. Square Foot: Most wood flooring is packaged in easily replace the builder-grade metal vents in square feet or square meters. This is the area that any floor. These vents normally are available in the flooring will cover. any species, in any size, and D. Board Foot: A board foot is a measurement of with or without volume that is 12” by 12” by 1” thick. The board dampers. foot measurement indicates the amount of lumber necessary to create flooring from a board. B. Flush-Mount or Trim-Line E. Line al Foot: Lineal foot is a measurement used Vents: A floor for ordering material when length is the only vent that is concern. Baseboards, transitions, feature strips, installed flush and borders are examples of materials commonly with, or cut ordered by the lineal foot. into, the wood F. Equal Lineal Foot: Random-width plank flooring floor. They laid in a repetitive pattern normally is ordered by may contain a the equal lineal foot to ensure that the floor gets frame in which the same length of each width of flooring. the removable G. Cubic Foot: A cubic foot (or 12” by 12” by 12”) is a vent rests. measurement normally only used when flooring These vents is being shipped in containers or via airfreight, are normally making volume a concern.
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PART IV Fraction - Decimal - Metric (mm)
Conversions and Calculations FRACTION DECIMAL METRIC (MM) A. Square Footage in a Bundle: (# of runs X bundle 11/32 .3438 8.78 length in feet X width in inches)/12 = ft2. 23/64 .3594 9.13 B. S quare Footage to Lineal Footage: (square feet X 12)/width in inches = lineal footage. 3/8 .3750 9.53 C. E qual Lineal Footage (for Multiple-Width 25/64 .3906 9.92 Flooring): Total square footage/total pattern 13/32 .4062 10.32 width X width in question = ft2. 27/64 .4219 10.72 D. A verage Length (with nested bundles): total 7/16 .4375 11.11 lineal feet/# pieces. 27/64 .4219 10.72 E. A verage Bundle Length (of bundled flooring): total lineal bundle feet/# of bundles. 7/16 .4375 11.11 F. C onverting fractions, decimals, and millimeters: 29/64 .4531 11.51 15/32 .4688 11.91 31/64 .4844 12.30 Fraction - Decimal - Metric (mm) 1/2 .5000 12.70 FRACTION DECIMAL METRIC (MM) 33/64 .5156 13.10 1/64 .0156 .4 17/32 .5313 13.49 1/32 .0313 .79 35/64 .5469 13.89 3/64 .0469 1.19 9/16 .5625 14.29 1/16 .0625 1.59 37/64 .5781 14.68 5/64 .0781 1.98 19/32 .5938 15.08 3/32 .0938 2.38 39/64 .6094 15.48 7/64 .1094 2.78 5/8 .6250 15.88 1/8 .1250 3.18 41/64 .6406 16.27 9/64 .1406 3.57 21/32 .6563 16.67 5/32 .1563 3.97 43/64 .6719 17.07 11/64 .1719 4.37 11/16 .6875 17.46 3/16 .1875 4.76 45/64 .7031 17.86 13/64 .2031 5.16 23/32 .7188 18.26 7/32 .2188 5.56 47/64 .7344 18.65 15/64 .2344 5.95 3/4 .7500 19.05 1/4 .2500 6.35 49/64 .7656 19.45 17/64 .2656 6.75 25/32 .7813 19.84 9/32 .2813 7.14 51/64 .7969 20.24 19/64 .2969 7.54 13/16 .8125 20.64 5/16 .3125 7.94 53/64 .8281 21.03 21/64 .3281 8.33 27/32 .8438 21.43 55/64 .8594 21.83 7/8 .8750 22.23 57/64 .8906 22.62 29/32 .9063 23.02 59/64 .9219 23.42 15/16 .9375 23.81 61/64 .9531 24.21 31/32 .9688 24.61 63/64 .9844 25.00
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The guidelines defined in this chapter generally are considered to be typical responsibilities of each involved party within the supply-chain. It is important to identify each of the relevant parties, along with their specific roles, prior to beginning each flooring project. Each party may be referenced by an alternative name or classification, may have more than one designation, or may be called something different from what is defined in this chapter. Defining responsibility will help all involved parties clearly understand their roles in the process, and assist in minimizing potential future claims.
PART I PART II Involved Party Definitions Involved Party Manufacturer: Any individual or entity that physically Responsibilities manufacturers a product, or has a product designed A. Manufacturer Responsibilities or manufactured for the wood flooring industry, 1. It is the responsibility of the Manufacturer to and places it on the market under its’ own name or produce a product, that will perform as it is trademark. marketed and intended to perform based on Specifier: Any individual or entity (including, but not the instructions provided. limited to, architects, builders, consultants, design 2. It is the responsibility of the Manufacturer to centers, interior designers/decorators, end-users, design and manufacture a product in general contractors, flooring contractors, sales accordance with all standards and regulations professionals) that recommends, specifies, or in any that apply to the product being sold. way advises the buyer prior to ordering, purchasing, 3. The product should contain labels identifying and/or installing the wood floor products. its contents, and should make available (in Supplier: Any individual or entity (including, but not print or electronically), installation and limited to, distributors, wholesalers, importers) that maintenance instructions for the product receives product from a manufacturer and supplies being put to use. the wood flooring products to a reseller or buyer. B. Specifier Responsibilities Seller: Any individual or entity (including, but not 1. It is the responsibility of the Specifier to limited to, retail stores, big box stores, internet sales, ensure that all jobsite conditions are capable interior designers, vendors, direct sales) that physically of meeting or exceeding the minimum supplies/sells the wood flooring products to the buyer. standards and requirements of the products being specified for the project. Buyer: Any individual or entity (including, but not 2. The specified wood floor must coincide with limited to distributors, end-users, installers, flooring the projected interior climate capabilities of contractors, general contractors) that is the first to the facility receiving the wood floor. Interior use/handle/possess/receive/deliver the wood flooring climate capabilities of the facility include type material prior to installation of the wood flooring and functionality of the HVAC systems, product. humidification/dehumidification systems, Builder: Any individual or entity (including, but interior and exterior insulation, types of not limited to homebuilders, remodelers, general/ windows, and methods of construction. restoration contractors, DIYers) that coordinates and 3. Interior environmental conditions vary from oversees the different suppliers, trades, installers, and region to region and jobsite to jobsite. The other experts involved in building or remodeling a wood floor selection should be determined by home, office, or other building. the interior climate capabilities of the facility Installer: Any individual or entity that physically installs receiving the wood flooring. The floor and places into service the wood flooring product. selection determination may include species, cut, width, installation method, manufacturer End User: Any individual or entity that physically requirements, or whether to use solid or receives and uses the final wood flooring product. engineered flooring for each unique situation.
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C. Supplier/Seller Responsibilities E. Installer Responsibilities 1. It is the responsibility of the Supplier and/or 1. It is the responsibility of the Installer to the Seller to ensure all products being recheck the jobsite conditions at the time of supplied meet or exceed the minimum federal installation and to confirm that they meet or and local regulations where it is being sold. exceed the wood flooring manufacturer’s 2. Product should be stored in dry, climate- requirements. controlled, and well-ventilated facilities that 2. It is the responsibility of the Installer, and/or meet the minimum requirements of the the Buyer and/or the End-User to ensure products being stored and sold. that the wood flooring product meets their 3. Products should not be sold to, or delivered expectations for visual appearance and to, a jobsite that does not meet manufacturer manufacturing quality prior to installation. minimum requirements, or the minimum Prior to commencing installation, the Seller, requirements detailed in the Jobsite Installer, Buyer, and End-User should, Conditions chapter of this publication. when possible, loose-lay several boards on 4. Expired/outdated product should not be sold the floor in the room where they will be without clear acknowledgment by the buyer. installed. If the visual appearance, color, sheen, or manufacturing quality of the D. Builder Responsibilities product is deemed unacceptable, it should 1. If the wood floor installation is part of the not be installed. scope of the construction project, it is the 3. Installation of flooring constitutes acceptance responsibility of the Builder to ensure that of the material and the site conditions at the all wet work (e.g., drywall taping, painting, time of installation. texturing, tile work, etc.) is completed and thoroughly dry prior to wood flooring F. End-U ser Responsibilities installation. 1. It is the responsibility of the End-User to 2. Building codes establish minimum standards use the flooring product as it is intended to and not always best practices. The Builder be used. must be aware of the materials specified 2. Post-installation, it is the responsibility of within the home in order to build accordingly. the End-User to maintain temperature and Any additional building costs must be humidity levels year-round, as required by accounted for during the specification the flooring manufacturer. and planning phases of construction. 3. It is the responsibility of the End-User to 3. In new construction, it is the responsibility follow a maintenance routine and use the of the Builder and/or the Specifier to proper maintenance products as required ensure the facility being built is designed by the flooring and finish manufacturers. and capable of sustaining an environment conducive to the building materials being used in it. The jobsite must meet or exceed all wood flooring manufacturer requirements and NWFA Guidelines prior to wood flooring delivery and installation. 4. It is the responsibility of the Builder to ensure moisture control policies have been put in place and implemented to protect all building components, including, but not limited to, wood flooring, prior to, and during, the entire construction process. Some porous materials (e.g., gypsum, plywood, and oriented strand board) can tolerate short-term wetting, but they must be dry before wood flooring installation (according to the US Environmental Protection Agency). 5. In water restoration projects, it is the responsibility of the Builder and/or the restoration company to meet the minimum moisture requirements as outlined in these Guidelines.
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The jobsite should meet, or exceed, all manufacturer requirements and NWFA Guidelines prior to wood delivery and before, during, and post installation.
PART I (ASHRAE). The Climate Zone designations in the map are specifically used to determine details Exterior Climate about different methods of construction based on the climate in which the building is being Considerations constructed. (Refer to the Regional Climate A. R egional Climate Variations: The average Variations publication for more detailed outdoor temperature and humidity varies from information.) region to region. Across every region, wood C. As the wood flooring professional, you should have floors can successfully be installed; however, a general understanding of the geographic climate all wood floors cannot be installed in the same zone for the location of the building that is receiving manner in all climate regions. The regional the wood floor. Use the climate zone maps, the MC variability of the exterior climate will affect the maps, and the experience and understanding you indoor conditions of the space. have of your region, to determine the seasonal B. The climate zone map has been adopted by ranges (high MC and low MC) in the area in which many organizations including the U.S. Department the floors are being installed. This information of Energy (US DOE), the International Energy will allow you to determine whether the interior Conservation Code (IECC), the International Code conditions of the space can accommodate the Council (ICC), and the American Society of Heating, flooring being installed, and to determine best Refrigerating and Air Conditioning Engineers installation practices.
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PART II Exterior Conditions of the Building Check the exterior of the structure to ensure the jobsite is ready to receive wood floors. Walk around the structure to identify any potential concerns that may affect your wood floor installation. Document, take photographs, and address all concerns with the homeowner and/or builder.
A. Gr ade 1. Grade Level: Note the grade level where the flooring is to be installed to ensure the flooring selected is appropriate. a. Above-grade is defined as any portion of the subfloor where wood flooring is to be installed, that is above the plane of the surrounding ground. b. On-grade is defined as any portion of B. Site Drainage the subfloor where 1. Exterior surface drainage (e.g., gutters, wood flooring is to be installed, that landscaping) should direct water away from is at, or above, the same plane as the the building. Water from rain, snowmelt, surrounding ground. nearby water sources, and irrigation systems c. Below-grade is defined as any portion can naturally travel toward the foundation of the subfloor where wood flooring is and into the structure. to be installed, that is 3” or more below 2. Lots should be graded to drain surface water ground level. away from foundation walls. Normal building 2. Engineered wood floors can be installed code requires a minimum fall of 6” (152 mm) above-grade, on-grade, and below-grade. within the first 10 feet (3.048 m). Impervious 3. Solid flooring can be installed on-grade and surfaces (pavement) should be sloped a above-grade, but should not be installed minimum of 2 percent away from the building. below-grade unless otherwise recommended 3. If any obvious concerns are observed related by the flooring manufacturer. to the exterior site drainage, they should be addressed by a qualified landscape professional prior to wood flooring delivery or installation.
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PART III Building Thermal Envelope A. The building thermal envelope includes the exterior walls, basement walls, floors, roof, and any other building element that encloses conditioned space. B. Building interiors are affected by two distinct humidity seasons – heating and cooling. Temperature and moisture (vapor) move from warmer/drier spaces to cooler/wetter spaces; this is known as vapor drive. 1. The moisture vapor moves from the warm side of the building assembly to the cold side of the building assembly. 2. In the summer, and in hot/ humid climates, during the interior cooling season, vapor drive is predominately inward. Cooling systems lower the temperature of the interior air. Cooling the air decreases its ability to hold moisture and the interior relative humidity naturally increases. Fortunately, air conditioning cools the air by removing moisture through condensation. 3. In the winter, during the interior heating season, vapor drive is predominately outward. Heating systems raise the temperature of the interior air. Heating the air will increase its ability to hold moisture; therefore, the interior relative humidity decreases.
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C. T he flooring installer should identify where, within the building, the wood floor is being installed in relation to other adjacent unconditioned spaces. 1. Conditioned space is an area or room within the building that is intentionally heated or cooled, and humidified or dehumidified, to be maintained at the same expected conditions as the living/ interior space either for the comfort of occupants, or for preserving temperature and humidity- sensitive goods.
2. Unconditioned space refers to exterior space, or a space within the shell of a building, that is uncontrolled, and is neither directly nor indirectly heated, cooled, humidified, nor dehumidified.
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PART IV Interior Conditions The conditions in the space in which the wood flooring is being installed will directly affect the performance of the wood floors. Wood flooring should not be delivered, stored, nor packages opened, on a jobsite or within any facility with uncontrolled environmental conditions, or that is outside of the conditions set forth by the manufacturer (temperature and RH) of the flooring product. Unless otherwise defined by the flooring manufacturer, follow these Guidelines as related to the F. Test and document the temperature and relative interior conditions of the building at the time the wood humidity in each of the room(s) where flooring is flooring is being delivered to the jobsite. being installed. A. Wood flooring should be one of the last jobs 1. For factory-finished solid and engineered wood completed in any remodel or new construction flooring, always follow the manufacturer’s project. requirements for interior temperature and relative humidity requirements. B. Do not deliver wood flooring to any jobsite, or install wood flooring, until the envelope of the 2. As a general rule for solid wood flooring, structure is fully enclosed and protected from with geographic exceptions, appropriate exterior weather conditions with all windows, temperature and humidity conditions are doors, exterior siding, soffits, roof coverings, defined as those conditions where the interior insulation, and ventilation in place. environment is controlled to stay within a relative humidity range between 30% to 50% C. All exterior doors and windows must be installed and a temperature range between 60-80 and in good repair in the specific locations, and in degrees Fahrenheit. These ranges are likely to adjacent rooms, to where wood flooring is being be the average of all types of wood products installed. If any issues are present, they should used in normal household environments, be repaired by a qualified professional before assuming common heating and cooling flooring is delivered to the jobsite or installed. equipment is used to ensure human comfort. D. Do not deliver or install wood flooring to the 3. Some manufacturers intentionally produce jobsite, until all “wet-trades” such as concrete, flooring products at higher (8-13%) or lower masonry, plastering, drywall, texturing, painting, (4-9%) moisture content levels to and power washing are completed within the accommodate different geographical regions. In building thermal envelope. some climates, the ideal average humidity range E. Verify that the facility can be higher (45% to 65%) or lower (20% receiving new flooring to 40%). Know your region and the flooring has permanent or product specified for the project to determine temporary mechanical whether they are properly aligned before systems (heating, selling and delivering material to the jobsite. cooling, humidification, G. Ensure the substrate receiving the wood floor or dehumidification) meets all minimum standards detailed in the capable of achieving and maintaining the applicable Substrates chapter. required conditions necessary for the wood H. The space below the flooring system should be flooring being installed. free of any evidence of standing water and high 1. These systems should be operating for a humidity levels. minimum of 5 days preceding delivery of flooring materials. Longer operation of HVAC I. IMPORTANT: Never install a wood floor over a systems and jobsite conditioning may be known moisture condition. A known moisture necessary prior to flooring delivery due to condition is one that you are aware of, and could tighter building envelopes and wet conditions. pose future damage to the flooring, the building, or the occupants. It is compulsory practice to 2. These same conditions should be maintained always test for moisture regardless of conditions prior to, during, and after wood flooring so that any unknown conditions can become installation. known conditions that then can be handled 3. Note that the use of temporary propane appropriately. In all cases, it is important that the heating systems will introduce moisture to installer consult with all involved parties including the environment. Large amounts of water are the manufacturer and customer. produced with the combustion of propane. Propane systems should be avoided prior to, J. Where the minimum jobsite conditions are during, and after wood flooring installation. present, the flooring may be delivered to the rooms in which it will be installed.
32 © 2019 NATIONAL WOOD FLOORING ASSOCIATION NATIONAL WOOD FLOORING ASSOCIATION TECHNICAL PUBLICATION ACCLIMATION/CONDITIONING
The process of aligning the wood flooring and the environment it is to be installed in is defined as acclimation, or more accurately, conditioning. This process involves understanding that the wood flooring and the facility are compatible. Unless otherwise directed by the flooring manufacturer, the following guidelines should be followed for acclimation/conditioning of each type of wood flooring. The values on the accompanying map provide examples of how average moisture contents (MC) for interior use of wood products vary from one region to another, and from one season to another within a region. The United States Department of Agriculture (USDA) Forest Products Laboratory suggests the following MC average and ranges for interior wood products: • Most areas of the United States: average = 8% MC, ranging from 6-10% MC • Dry southwestern regions: average = 6% MC, ranging from 4-9% MC • Damp, warm coastal areas: average = 11% MC, ranging from 8-13% MC Actual interior MC conditions in any location may differ significantly from these numbers.
MOISTURE MAP OF NORTH AMERICA
9-13
5-9
6-9 6-9 6-9 6-9
6-11 6-11 8-12
9-13 6-12
6-9 6-11 6-12 8-13 6-7 5-9 6-11 6-11 5-10 7-10 5-7 6-10 7-12 7-8 5-7 6-9 7-11 6-7 5-9 7-10 6-9 7-13 7-8 7-10 4-7 7-9 7-10 8-11 4-7 5-6 8-12 8-11 4-8 6-7 7-8 7-9 8-9 8-13 8-10 8-11 5-8 8-10 9-11 9-13 6-8 8-9 8-9 9-119-11 9-12 4-10 7-9 5-9 11-12 11-13 8-13 8-13 8-10 12-13 4-10 11-13 5-9 11-13 12-13 6-9 6-13
9-11 8-13 7-9 6-9
6-7 9-11
9-11 6-7 6-8 6-86-8 12-13 9-11 7-86-8 9-11 12-13 9-11 7-9 7-9 12-13 9-11 7-108-10 9-11 12-13 12-13 11-13 11-13 11-13 11-13
The numbers on the accompanying© 2019 map NATIONAL provide examples WOOD FLOORINGof how average ASSOCIATION moisture contents for interior use of wood 33 products vary from one region to another, and from one season to another within a region. Actual moisture content conditions in any location may differ significantly from these numbers. NATIONAL WOOD FLOORING ASSOCIATION TECHNICAL PUBLICATION
PART I 1. After calibrating your meter to the subfloor material being tested, take MC readings in Solid Wood Flooring a minimum of 20 test locations for up to the A. Prior to delivery of the wood flooring, check first 1,000 square feet, and an additional and record the jobsite ambient conditions and 4 readings per 100 square feet thereafter, the subfloor moisture to ensure they coincide and average the results. Testing locations with the wood flooring requirements that have should be representative of the entire project been selected. and include a minimum of three tests per room receiving wood. Pay special attention B. Upon delivery of the flooring to the jobsite, to exterior walls and plumbing. Elevated recheck and record the temperature and relative readings should be addressed prior to humidity in the space receiving the wood floor. delivery and installation of any wood flooring. The temperature and humidity must be within In general, more readings will result in a the manufacturer’s requirements. more-accurate average. Record, date, C. Upon delivery of the flooring to the jobsite, photograph, and document all results. recheck and record the MC of multiple boards 2. The average of the wood subfloor readings of flooring from a variety of bundles. Check with should coincide with the manufacturer- your moisture meter manufacturer to determine required temperature and humidity levels the correct setting on your meter for the wood in the facility receiving wood flooring. Where species being tested. the wood subfloor MC is not aligned with 1. Take MC readings of the wood flooring on the required conditions in the facility a minimum of 40 boards for up to the first receiving wood, the general rule of thumb 1,000 square feet, and an additional 4 is to ensure the MC of the wood subfloor readings per 100 square feet thereafter, and is no more than 4% greater than the MC of average the results. With pin-type moisture solid strip (<3” widths) wood flooring, and meters, tests should be taken on the back no more than 2% greater than the MC of of the boards to avoid damage to the face of solid plank (≥3” widths) wood flooring the flooring. In general, more readings will being installed. result in a more-accurate average. Record, 3. Concrete subfloors must be moisture tested, date, photograph, and document all results. and adequate moisture control systems 2. The readings should coincide with the should be in place prior to installation of required temperature and humidity in the any solid wood floor. facility receiving wood flooring. The table 4. Any unusually high or low subfloor moisture below indicates the predicted equilibrium readings should be isolated and addressed moisture content of wood at any given prior to wood floor installation. combination of temperature and relative E. W hen the wood flooring is delivered at a MC humidity. that coincides with the expected in-use (e.g., 3. Any unusually high or low moisture readings normal living) and manufacturer’s required should be isolated and not installed in ambient conditions within the facility, and this the floor. coincides with the subfloor moisture conditions, D. Upon delivery of the flooring to the jobsite, and these conditions are being maintained, recheck and record the MC of the subfloor. the flooring may be installed immediately. Check with your moisture meter manufacturer to determine the correct setting on your meter for the wood subfloor being tested.
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AT VARIOUS TEMPERATURE MOISTURE CONTENT OF WOOD AND RELATIVE HUMIDITY READINGS oF oC 30 -1.1 1.4 2.6 3.7 4.6 5.5 6.3 7.1 7.9 8.7 9.5 10.4 11.3 12.4 13.5 14.9 16.5 18.5 21.0 24.3 40 4.4 1.4 2.6 3.7 4.6 5.5 6.3 7.1 7.9 8.7 9.5 10.4 11.3 12.4 13.5 14.9 16.5 18.5 21.0 24.3 50 10 1.4 2.6 3.7 4.6 5.5 6.3 7.1 7.9 8.7 9.5 10.4 11.3 12.4 13.5 14.9 16.5 18.5 21.0 24.3 60 15.6 1.3 2.5 3.6 4.6 5.4 6.2 7.0 7.8 8.6 9.4 10.2 11.1 12.1 13.3 14.6 16.2 18.2 20.7 24.1 70 21.1 1.3 2.5 3.5 4.5 5.4 6.2 6.9 7.7 8.5 9.2 10.1 11.0 12.0 13.1 14.4 16.0 17.9 20.5 23.9 80 26.7 1.3 2.4 3.5 4.4 5.3 6.1 6.8 7.6 8.3 9.1 9.9 10.8 11.7 12.9 14.2 15.7 17.7 20.2 23.6 90 32.2 1.2 2.3 3.4 4.3 5.1 5.9 6.7 7.4 8.1 8.9 9.7 10.5 11.5 12.6 13.9 15.4 17.3 19.8 23.3 100 37.8 1.2 2.3 3.3 4.2 5.0 5.8 6.5 7.2 7.9 8.7 9.5 10.3 11.2 12.3 13.6 15.1 17.0 19.5 22.9 120 48.9 1.1 2.1 3.0 3.9 4.7 5.4 6.1 6.8 7.5 8.2 8.9 9.7 10.6 11.7 12.9 14.4 16.2 18.6 22.0 140 60 0.9 1.9 2.8 3.6 4.3 5.0 5.7 6.3 7.0 7.7 8.4 9.1 10.0 11.0 12.1 13.6 15.3 17.7 21.0 160 71.1 0.8 1.6 2.4 3.2 3.9 4.6 5.2 5.8 6.4 7.1 7.8 8.5 9.3 10.3 11.4 12.7 14.4 16.7 19.9 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 Realitive Humidity (percent)
F. A djusting the MC of the solid wood flooring 2. Conditioning of solid wood in these may be necessary under either of the following environments can be facilitated by separating circumstances: 1 - When the MC of the wood the flooring into small lots and/or completely flooring product is different from the expected opening the packaging. Then cross stack the in-use conditions of the facility, or 2 - In extreme materials with spacers (3/4” to 1” stickers) environments. between each layer of flooring to allow air 1. CAUTION: Altering the MC of any wood circulation on all sides of all boards until EMC product, in order to accommodate extreme has been reached. conditions, involves introducing or removing 3. Off-site conditioning of the flooring material moisture from the wood prior to installation. in a controlled environment is possible when When doing so, the change in moisture may the off-site conditions reflect the flooring cause the floor boards to shrink or swell manufacturer’s requirements and the outside of the manufactured dimension. expected in-use (normal living) conditions. Solid wood generally will not take-on or 4. Imported/tropical species often require two give-up moisture, nor will it change dimension, to three times longer equilibrating to their uniformly. This may adversely affect the surroundings than most domestic species due installation, and should be taken into account to higher overall density, oil, and resin content, when bidding the project and installing and their interlocking cell structure. Take this the flooring. additional time into account when scheduling the project. G. W ith unfinished solid wood flooring, after installation and before sanding and finishing takes place, and when scheduling allows, allow the flooring to stabilize in its new environment for 5-7 days. Flooring installed using an adhesive application system may require a longer post- installation conditioning period to allow all residual off gassing to occur prior to application of a finish. Follow the adhesive manufacturer’s recommendations for dry times and off-gassing prior to sanding and finishing.
© 2019 NATIONAL WOOD FLOORING ASSOCIATION 35 NATIONAL WOOD FLOORING ASSOCIATION TECHNICAL PUBLICATION
PART II PART III Engineered Wood Flooring Parquet and End-Grain A. Prior to delivery of the wood flooring, check and Wood Flooring record the jobsite ambient conditions and the A. Prior to delivery of the wood flooring, check and subfloor moisture to ensure they coincide with record the jobsite ambient conditions and the the wood flooring requirements that have been subfloor moisture to ensure they coincide with selected. the wood flooring requirements that have been B. Upon delivery of the flooring to the jobsite, selected. recheck and record the temperature and relative B. Upon delivery of the flooring to the jobsite, humidity in the space receiving the wood floor. recheck and record the temperature and relative The temperature and humidity must be within the humidity in the space receiving the wood floor. manufacturer’s requirements. The temperature and humidity must be within the C. Upon delivery of the flooring to the jobsite, manufacturer’s requirements. recheck and record the MC of the subfloor. Check C. Upon delivery of the flooring to the jobsite, with your moisture meter manufacturer to recheck and record the MC of multiple panels or determine the correct setting on your meter for blocks from a variety of packages. Check with the wood subfloor being tested. your moisture meter manufacturer to determine 1. Take MC readings of the wood subflooring at the correct setting on your meter for the wood a minimum of 20 test locations per 1,000 species being tested. square feet, and an additional 4 readings per 1. For parquet or end-grain flooring, take MC 100 square feet thereafter, and average the readings on a minimum of 40 panels/blocks results. In general, more readings will result per 1,000 square feet, and an additional 4 in a more-accurate average. Any unusually readings per 100 square feet thereafter, and high or low moisture readings should be average the results. With pin-type moisture isolated and addressed individually. Record, meters, tests should be taken on the back of date, photograph, and document all results. the wood to avoid damage to the face of the 2. The average of the wood subfloor readings flooring. In general, more readings will result should coincide with the manufacturer- in a more-accurate average. Record, date, required temperature and humidity levels photograph, and document all results. in the facility receiving wood flooring. (Refer 2. The readings should coincide with the to the MC chart in Part I of this chapter.) required temperature and humidity in the 3. Concrete subfloors must be moisture tested, facility receiving wood flooring. and adequate moisture control systems 3. Any unusually high or low moisture readings should be in place prior to installation of any should be isolated and not installed in the floor. solid wood floor. 4. Any unusually high or low subfloor moisture D. Upon delivery of the flooring to the jobsite, readings should be isolated and addressed recheck and record the MC of the subfloor. prior to wood floor installation. Check with your moisture meter manufacturer to determine the correct setting on your meter D. Follow the flooring manufacturer’s moisture for the wood subfloor being tested. testing, acclimation, installation, and maintenance 1. Take MC readings of the wood subflooring instructions to retain all warranty coverage. at a minimum of 20 test locations per 1,000 E. When the wood flooring is to the expected in-use square feet, and an additional 4 readings per (e.g., normal living) and manufacturer’s required 100 square feet thereafter, and average the ambient conditions within the facility, and this results. In general, more readings will result in coincides with the subfloor moisture conditions, a more-accurate average. Any unusually high and these conditions are being maintained, the or low moisture readings should be isolated flooring may be installed immediately. and addressed individually. Record, date, F. With unfinished engineered wood flooring, after photograph, and document all results. installation and before sanding and finishing 2. The average of the wood subfloor readings takes place, and when scheduling allows, let should coincide with the manufacturer the flooring stabilize in its new environment required temperature and humidity levels for a period of time. Flooring installed using an in the facility receiving wood flooring. Where adhesive application system may require a longer the wood subfloor MC is not aligned with the post-installation conditioning period to allow all required conditions in the facility receiving residual off-gassing to occur prior to application wood, the general rule of thumb is to ensure of a finish. Follow the adhesive manufacturer’s the MC of the wood subfloor is no more than recommendations for dry times and off-gassing. 4% greater than the MC of parquet wood
36 © 2019 NATIONAL WOOD FLOORING ASSOCIATION NATIONAL WOOD FLOORING ASSOCIATION TECHNICAL PUBLICATION
flooring, and no more than 2% greater than boards. Conditioning end-grain flooring can the MC of end-grain wood flooring being be facilitated by separating the individual installed. blocks into small lots and then restacking 3. Concrete subfloors must be moisture tested, them, on-edge, in the expected in-use (e.g., and adequate moisture control systems normal living) conditions of the facility. The should be in place prior to installation of lower and more spread out the blocks are any solid wood floor. laid out, the faster the conditioning process 4. Any unusually high or low subfloor moisture will take. readings should be isolated and addressed 3. Imported/tropical species often require two prior to wood floor installation. to three times longer equilibrating to their surroundings due to higher overall density, E. When the wood flooring is delivered at a MC that oil and resin content, and their interlocking coincides with the expected in-use (e.g., normal cell structure. Take this additional time into living) and manufacturer’s required ambient account when scheduling the project. conditions within the facility, and this coincides with the subfloor moisture conditions, and these 4. Off-site conditioning of the flooring material in conditions are being maintained, the flooring a controlled environment is possible when the may be installed immediately. off-site conditions reflect the expected in-use (normal living) conditions. F. In cases where the MC of parquet or end-grain flooring is outside of the range of the expected G. A fter installation, and before sanding and finishing in-use (e.g., normal living) conditions, or in takes place, allow the flooring to stabilize in its extreme environments, conditioning of the new environment for 5-7 days, when scheduling flooring may be necessary. allows. Flooring installed using an adhesive application system may require a longer post- 1. Altering the MC of the flooring, in order to installation conditioning period to allow all accommodate extreme conditions, involves residual off-gassing to occur prior to application introducing moisture or removing moisture of a finish. Follow the adhesive manufacturer’s from the flooring prior to installation. When recommendations for dry times and off-gassing. doing so, the change in moisture may cause the material to shrink or swell outside of the manufactured dimension. This may adversely affect the installation, and should be taken PART IV into account when bidding the project and Reclaimed Wood Flooring installing the flooring. A. Reclaimed lumber that has been milled into solid wood flooring must be dried to a MC that coincides with the home and the environment in which it is being installed. B. Prior to delivery of the wood flooring, check and record the jobsite ambient conditions and the subfloor moisture to ensure they coincide with the wood flooring requirements. C. Upon delivery of the flooring to the jobsite, recheck and record the temperature and relative humidity in the space receiving the wood floor. The temperature and humidity must be within the manufacturer’s requirements and the requirements that the facility can sustain year-round. D. Upon delivery of the flooring to the jobsite, recheck and record the MC of multiple boards of flooring from a variety of bundles. Check with your moisture meter manufacturer to determine the correct setting on your meter for the wood species being tested. E. An y reclaimed wood flooring should be acclimated the same as detailed in the applicable 2. Due to the orientation of the grain, end-grain wood flooring section (e.g., reclaimed solid, flooring tends to equilibrate at a relatively reclaimed engineered, reclaimed parquet, or fast rate (depending on thickness and reclaimed end-grain). species) as compared to other solid sawn
© 2019 NATIONAL WOOD FLOORING ASSOCIATION 37 NATIONAL WOOD FLOORING ASSOCIATION TECHNICAL PUBLICATION MOISTURE TESTING
The determination of moisture content is an essential part of quality control within the flooring installation process. Flooring installers must know the ambient conditions in the space, the moisture content of the wood flooring, and the moisture content of the substrate. Hand-held thermo-hygrometers and electronic moisture meters should be a critical part of every flooring contractor’s toolbox. Moisture content (MC) from 5-30% may be determined using various moisture meters developed for this purpose.
4. Cooling the air will decrease its ability to hold moisture; therefore, for the same physical amount of water, the relative humidity increases (absolute humidity remains the same). 5. Humidity is important because wood products exchange water molecules from the surrounding air based upon the amount of moisture in the air. B. T est the temperature and relative humidity in the room(s) where the flooring is being installed. C. Hygrometers: Instruments used for measuring the amount of water vapor in the air. There are a few types of these instruments, but in modern times, we employ digital thermo- hygrometers. PART I These tools Temperature/Relative typically can read Humidity temperature, The moisture content in wood is directly affected by relative temperature and humidity. humidity, and A. In order to understand why temperature oftentimes properties like absolute humidity and humidity affect wood, it is important and dew point as well. Many of today’s thermo- to understand the relationship between hygrometers are wireless, have data logging, and temperature and humidity. even have remote capabilities. 1. Temperature is simply a measurement that D. Data Loggers: An electronic device that records indicates how hot or cold something is. In the and stores data over time or in relation to United States we use the Fahrenheit (°F) location, either with a built-in instrument or scale. The majority of the rest of the world sensor or via external instruments and sensors. uses the Celsius (°C) scale. These instruments are oftentimes left on the 2. Humidity is the amount of water vapor in the jobsite in order to monitor the conditions in air. This air/water vapor mixture, when the space prior to, during, and after wood measured as the actual moisture in a given flooring installation. volume of air (or grains/ft3) is the absolute E. T he “EMC of Wood at Various Temperature humidity (Habsolute). In regular usage, however, and Relative Humidity Readings” table in the we use the term relative humidity (RH), which Acclimation/Conditioning chapter, provided by is the ratio of the amount of moisture the air USDA Forest Products Lab, indicates a reasonable is holding in comparison to the total amount representation of the predicted Moisture Content of moisture the air can hold at the same (MC) of wood at any given combination of temperature. No matter how the property of temperature and relative humidity. Use the values humidity is expressed, the values are very in this table to approximate the average MC of much temperature dependent. the wood based on the temperature and humidity 3. Heating the air will increase its ability to hold readings in the facility. You also can use this chart moisture; therefore, for the same physical to determine approximate change in moisture amount of water, the relative humidity content based on a seasonal change in conditions decreases (absolute humidity remains the same). within the facility.
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PART II b. Signal penetration for these types of meters can be from ¼ ” up to 1 ½ ”. Moisture Testing Wood c. These meter readings are dependent on A. Oven Dry Method (Laboratory Test) material density and specific gravity. 1. The moisture content (MC) of wood is d. The meter can be moved across the measured as the weight of the water in the surface to test multiple areas for wood expressed as a percentage of the weight moisture in a wood block or plank. of the wood itself. The weight of the wood itself e. Some of these types of meters can be is obtained when the wood is dried to a point sensitive to surface moisture, but where all of the moisture is removed. This is relatively unaffected by temperature referred to as oven-dried. Weight, shrinkage, (check with the meter manufacturer). strength, and other properties depend in part f. Measurements can also be taken through on the moisture content of wood. coatings without damage to the surface. 2. Standard Test Methods for Direct Moisture However, some coatings with metallic Content Measurement of Wood and Wood- components may affect the accuracy of Based Materials (Oven Dry Method – ASTM the readings. D4442): 2. Pin-Type Meters a. This method is generally accepted for a. The pin-type meters measure the basic laboratory work and as a standard electrical resistance across opposing sets for calibrating other test methods. This is of pins, which are pushed into the wood. because the oven-dry test method is the b. Placement of the pins in relation to grain most precise test method to determine orientation is manufacturer and meter gravimetric moisture content. specific. This depends on the international b. This test method requires weighing the standard to which the meter is calibrated. piece of wood with moisture, removing Check with your meter manufacturer for the moisture by fully drying it in an oven proper use. (215°F-220°F or 102°C-105°C) and then c. These types of meters force an electrical reweighing. The equation for determining current through the wood sample moisture content is as follows: between the probes. Because wood is a poor conductor of electricity and water is a good conductor of electricity, wood with (weight of wood with water – oven-dry weight of wood) higher MC has a lower resistance. The x 100 = MC (%) results are displayed as a number that oven-dry weight of wood represents a moisture content percentage. d. Pin-type meters are available with either insulated or non-insulated pins: B. Mois ture Meters: There are two main types of meters: pinless meters (dielectric) and pin-type meters (electrical resistance). Both types of meters will give generally reliable readings from as low as 5% MC, up to the fiber saturation point (FSP) of the species being tested.
i. Non-insulated pins will read as deep as they are inserted and will report the highest value of resistance 1. Pinless Meters through the entire depth of the pins. a. The pinless, dielectric types are also referred to as non-invasive, non- destructive, scanning, or surface meters.
© 2019 NATIONAL WOOD FLOORING ASSOCIATION 39 NATIONAL WOOD FLOORING ASSOCIATION TECHNICAL PUBLICATION
meter properly calibrated. Many meter manufacturers will provide a calibration certificate, which verifies National Institute of Standards and Technology (NIST) traceability and that the meter is operating properly. 3. Meter Drift a. Meter drift is the decrease (or increase) in true moisture content over a specified elapsed time. b. Record readings from your meter within the first 2-3 seconds to ensure accuracy. ii. Insulated pins are typically available in 4. Temperature Correction many different lengths, from 1”-3”, and a. The temperature of the wood will are normally used with a slide hammer significantly influence the readings of a extension. Insulated pins only measure pin-type meter. the resistance at the uninsulated tips b. Temperature correction is the adjustment of the pins, allowing one to evaluate that is made to the moisture meter reading the moisture gradients through the to compensate for the phenomena that sample of flooring, subflooring, or the electric conductance of wood increases the entire flooring system. as the temperature increases, and C. Moisture Meter Reading Variables vice-versa. This adjustment, whether 1. Species Correction manual or automatic, allows for accurate a. Most meter manufacturers calibrate their measurements of moisture content even at meters to pine/Douglas fir/hemlock. extreme temperatures (e.g., less than 50°F b. Species correction is a meter and greater than 90°F). manufacturer-specified, user-adjusted c. Use the following chart to determine the setting that is made to the moisture temperature correction based on the surface meter to compensate for either varying temperature of the wood being tested. electrical properties (for pin-type meters) or densities (for pinless meters) of the species under test, as compared to the TEMPERATURE CORRECTION species of the reference calibration. SURFACE METER READINGS TEMPERATURE c. Some meters have a species correction oF oC 6 7 10 15 20 25 30 35 40 50 60 adjustment built in, while others include 0 -17.8 9 11 15 22 31 38 45 53 conversion charts to account for species 20 -6.7 8 10 14 20 28 34 40 47 55 correction. 40 4.4 7 8 12 18 24 30 36 42 48 d. Making these adjustments allows for a 60 15.6 6 7 11 16 21 27 32 38 43 54 more-accurate assessment of the 80 26.7 6 7 9 14 19 23 28 33 38 47 55 moisture within the wood being tested. 100 37.8 5 6 8 12 17 21 25 29 34 42 50 2. Calibration 120 48.9 5 5 7 11 15 19 22 26 30 38 44 a. Calibration ensures the meter is giving 140 60 4 5 7 10 14 17 20 23 27 34 40 160 71.1 4 4 6 9 12 15 18 21 24 30 36
accurate readings. Moisture content values above the fiber saturation point are only qualitative. The temperature correction values shown in this chart have been rounded for easy reference. b. Calibration is usually considered the responsibility of the manufacturer, and 5. The materials within the depth of signal the user accepts the calibration data penetration can influence the readings the supplied with the meter. The accuracy of meter is taking. Substrate composition, calibration, especially in regard to adhesives, and engineered flooring core and sampling and specimen control, is backing components (different species or usually unknown to the user. composite materials) all can have different c. ASTM D4444 is the standard test method densities, specific gravities (pinless), or for laboratory standardization and electrical resistances (pin-type), which will calibration of handheld moisture meters. alter the end reading. For example, a ¾ ” deep d. Some meters can be checked for scan over a ½ ” engineered floor is also calibration internally or by use of a scanning the core, the flooring adhesive, and calibration block supplied by the the surface of the substrate. Check with the manufacturer. meter manufacturer for testing protocol, e. Check with the meter manufacturer to accuracy, and appropriate species correction determine if, when, and how to get your values when testing any engineered wood flooring product.
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6. Skill of the Operator: Although moisture average the results. Testing locations should be meters are normally very simple to operate, representative of the entire project and include there are many user-errors that can affect a minimum of three tests per room receiving the accuracy and reliability of the readings. wood. Pay special attention to exterior walls a. Are the batteries in the meter fresh? A and plumbing. Elevated readings should be weak battery can affect the readings the addressed prior to delivery and installation of meter is giving you. any wood flooring. In general, more readings will b. Follow all of the meter manufacturer result in a more-accurate average. Record, date, instructions on proper use of the tool. photograph, and document all results. c. Wood flooring material selection should D. T he MC of the subfloor should coincide with the be taken into account to achieve the real expected in-use (e.g., normal living) conditions objectives of the moisture measurements. of the facility, based on the EMC chart. Anything outside of this range would be considered unusually high. PART III E. In hot and humid climates, and during the humid season, the subflooring should not exceed Moisture Testing 13% moisture content (MC). In regions where Wood Subfloors equilibrium moisture content (EMC) within the facility can sustain these higher MC levels, At the time of installation, it is important to know the additional precautions should be implemented moisture content of not only the wood flooring, but of through the flooring product selection and the the substrate as well. acclimation/conditioning process (see Acclimation/ Conditioning chapter for more information). F. An y unusually high MC readings must be identified, documented, and addressed in order to establish the size and magnitude of the problem area. Installation should not proceed until the origin of the moisture has been identified and remedied. 1. IMPORTANT: Never install a wood floor over a known moisture condition. A known moisture condition is one that you are aware of, and could pose future damage to the flooring, the building, or the occupants. It is compulsory practice to always test for moisture regardless of conditions so that any unknown conditions can become known conditions, which then can be handled appropriately. 2. The traditional standard for protecting wood A. Due to the variability in wood subflooring and wood products from rot or decay is to materials, such as the different species of woods keep the moisture content below 19 percent. used in the production of wood subfloors, and Studies have shown, however, that mold the non-wood resins and adhesives used within growth can occur on wood at moisture them, it is difficult to get an accurate moisture content levels above 15 percent, and corrosion reading of this material. Check with the moisture of metal fasteners can occur when moisture meter manufacturer for proper settings, testing content exceeds 18 percent. Reaching these methods, and correction values when testing moisture content levels does not mean rot, wood subfloor materials. decay, mold growth, or corrosion will occur, B. W hen in doubt, check the moisture content but does raise a potential concern. In all cases, of other properly conditioned wood materials it is important that the installer consult with (2x4s, newel posts, wood beams, etc.) within the all involved parties including the manufacturer structure in order to get an idea of where the and customer. EMC is in comparison to where it should be, and G. Ano ther key variable of the moisture content of then compare this value with the EMC chart as a wood subfloors involves what is going on below baseline for testing the subfloor. the subfloor. C. A fter calibrating your meter to the subfloor 1. When the space below the subfloor is material being tested, take MC readings in a controlled and conditioned to the same minimum of 20 test locations for up to the temperature and RH as above the floor, the first 1,000 square feet, and an additional 4 moisture content through the thickness of readings per 100 square feet thereafter, and the subfloor material should be the same.
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2. When conditions below the subfloor are 1. ASTM 1869 unconditioned, the moisture content will vary Calcium Chloride: through the thickness of the subfloor system. A calcium chloride This difference may affect the installed wood moisture test is flooring and can result in damage. a standard test 3. Do not install a wood floor over an method for unconditioned space without addressing the measuring the moisture situation as detailed in the moisture vapor Underlayments: Moisture Control chapter. emission rate (MVER) of a concrete subfloor PART IV using anhydrous calcium chloride. The results of this test give Moisture Testing quantifiable values. Concrete Subfloors a. R esults are shown as pounds of water over a 24-hour period, per 1,000 square It is extremely important to test for moisture on every feet. flooring job. Even when the adhesive manufacturer b. Ambien t conditions must be 65°-85°F states “no moisture testing is required,” it is still in your and 40-60% relative humidity for best interest to moisture test, and document the results. a minimum of 48 hours prior to Doing so will minimize the risk of failure, it will meet conducting the test. the flooring manufacturer’s warranty requirements, it c. E ach prepared area must be 20”x 20,” will fulfill your contractual obligation as the flooring clean, and free of all foreign substances. professional, and it will minimize your liability if a failure does occur. In cases where there is not an effective d. Ligh tly grind the area to produce a vapor retarder in place directly below the slab, the surface profile equal to a concrete results of any type of moisture test are likely to increase surface profile (CSP) 1-2, a minimum as moisture from the ground will enter and raise the of 24 hours prior to testing. moisture level in the concrete once it is covered. e. W eigh the calcium chloride in its container. A. All concrete moisture tests indicate a condition of the concrete floor slab at the time of the test f. Plac e the opened calcium chloride under the ambient conditions of the test, and may container on the prepared area and not predict future conditions of the floor slab. immediately cover it with a transparent These tests do not indicate a permanent condition cover to create an airtight seal. of the substrate. This is especially true if an g. L et the covered container sit for 60-72 effective moisture vapor retarder is not present or hours undisturbed. has been compromised by damage or by improper h. R emove the transparent cover and installation. calculate as directed by the calcium B. C onduct tests to give you the ability to know chloride test kit manufacturer. when to start or not start a job, and to determine i. Plac e three kits in the first 1,000 square what products and systems will be necessary feet and one per every 1,000 square in order to install the floor. All concrete slabs, feet thereafter. regardless of age, will exhibit changes in j. R ecord the data. moisture over time. k. C oncrete slabs with a calcium chloride C. As concrete moves through its initial drying MVER reading of greater than 3 lbs/ period, regular testing of moisture content to 1,000 square feet/24 hour are strongly evaluate the drying condition of the slab may recommended to wait for further drying begin 30 days after placement. of the slab, or install/apply a minimum class 1 impermeable vapor retarding D. Appr opriate moisture testing, specified by the membrane over the slab according to flooring and/or adhesive manufacturer, is the the adhesive manufacturer’s only way to identify if moisture levels in the slab instructions, prior to installation. are adequate for the systems being used. E. All tests should be performed as dictated by the ASTM standard.
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2. A STM 2170 j. Record the data. Relative k. Alw ays follow manufacturer guidelines Humidity: Relative for testing procedure. humidity moisture l. C oncrete slabs with a RH reading of testing is the more than 80% are strongly standard test recommended to wait for further drying method for of the slab, or install/apply a class 1 determining impermeable vapor retarding membrane relative humidity according to the adhesive in concrete floor manufacturer’s instructions, prior to slabs using in-situ installation. probes. The results 3. ASTM F2659 Electrical Moisture Meter: of this test give Nondestructive electrical moisture meters quantifiable values are and may be used to test lightweight concrete the standard and gypsum-based underlayments. guide for a. T his method predicts what the equalized preliminary relative humidity will be through the evaluation entire thickness of the slab once it is of the covered with flooring material. comparative b. Normal living conditions should be moisture maintained for 48 hours prior to testing. condition of c. C alibration of reusable probes should be concrete, checked before every job, or if not used gypsum cement, and other floor slabs and for 30 days. screeds. It is a nondestructive testing d. T o perform the test, drill a hole in the method. These tests should be used to slab at the following thickness: evaluate the surface of the concrete and to i. If the slab is drying from top only determine where to place other quantifiable (e.g. slab on-grade or in fluted metal tests. These tests provide useful information, decking), drill holes to 40% of the but should not be used on their own to slab thickness. determine whether a floor should or should not be installed unless otherwise directed by ii. If the slab is drying from top and the flooring manufacturer. bottom (e.g., suspended slab), drill holes to 20% of the slab thickness. a. To ensure accuracy, the meter should be calibrated before every project or if not e. T he hole diameter is determined by the used for 30 days. manufacturer’s sleeve size. b. The interior environment of the jobsite f. T ests should be placed within 3 feet of should be 65°-85°F and 40-60% relative each exterior wall. humidity for at least 48 hours prior to g. C onduct three tests for the first 1,000 testing. square feet and one for every 1,000 c. The temperature of the floor slab is to square feet thereafter. be tested and reported within 8” of each h. Ins ert the sleeve, cap it, and allow it to test area. acclimate for a minimum of 24 hours. d. Eight tests should be conducted for the i. T he meter reading must not drift first 1,000 square feet and 5 additional more than 1% relative humidity over a tests should be conducted for each five-minute period. When leapfrogging additional 1,000 square feet with 3-5 reusable probes, allow at least 1 hour tests per test site. Be sure to record the to achieve a true 1% drift in 5 minutes. highest reading. Each test area should (Leapfrogging is when reusable probes be within a one-foot-by-one-foot area. are being used. An example would be a e. T his test shows a moisture condition in project where you have 50 holes drilled, the upper one-inch of the slab. lined and capped. However you only own 10 probes. When those ten probes are f. It is very useful for mapping areas for removed from the first 10 hole liners, further qualitative tests. allowed to acclimate with the ambient g. There are three types of electrical conditions, and then placed in the moisture meters: impedance, next ten liners, it is referred to as capacitance, and field charge detecting. “leapfrogging.”)
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4. Other tests that are not as common, but still b. ASTM in use, include: D4263 a. ASTM D4944 Plastic Calcium Sheet Carbide Gas Method: Pressure The plastic Test: This sheet test test method method is includes used to quantifiable indicate test the presence of capillary moisture in procedures for concrete. This test can provide useful determining information, but should NOT be used to moisture in determine whether a floor should or building should not be installed. and other i. T o conduct this test, tape an 18” x 18” materials. sheet of 4 millimeter poly to clean i. This test concrete. involves ii. Y ou should conduct one test area per taking samples of the concrete and 500 square feet. pulverizing them into a fine-grained iii. Allow the test to sit for 16 hours. material. The test material is then iv. A fter 16 hours have passed, lift the weighed. plastic. ii. T his material is then placed into a v. If a darkened area is visible, moisture testing chamber with an attached is present. pressure gauge, along with two vi. If there is not a dark area, it does steel balls and a calcium carbide not mean moisture is not present. reagent. More conclusive tests should always iii. T he testing chamber is sealed be conducted. closed, and then shaken vigorously for 2-5 minutes. This breaks up the calcium carbide that, when coming into contact with the water in the concrete, creates a highly flammable and explosive acetylene gas. iv. W hen the pressure gauge dial needle stops moving, the final pressure reading shows the percentage of water content in the dry mass of concrete. v. C oncrete slabs with a reading of more than 2.5% requires use of a class I vapor retarder. A reading of more than 4% may not be acceptable for the wood flooring to be installed.
44 © 2019 NATIONAL WOOD FLOORING ASSOCIATION NATIONAL WOOD FLOORING ASSOCIATION TECHNICAL PUBLICATION BASEMENTS AND CRAWLSPACES
PART I Foundation Walls Foundation issues translate to flooring issues. Cracks in foundation walls may be a larger sign of settling, structural damage, or water infiltration that will need to be fixed by a qualified contractor. A. Water can enter the home through these cracks, and can affect the wood subfloor above, as well as the wood flooring. B. T hese cracks may also be the result of structural issues that may affect the performance of the wood floor. C. Exp ansive soils are a type of clay or soil that is prone to large volume changes (swelling and shrinking) that are directly related to changes in soil C. In unfinished basements, the heating and water content. Areas with an abundance of this type air conditioning is often not turned on, or is of soil can exert pressure on a foundation potentially maintained differently than the upstairs living resulting in foundation, basement, or slab problems, spaces, in an effort to reduce wasted energy and which can translate to flooring problems. perceived unnecessary costs. This is considered an unconditioned space. Unconditioned basements are typically cooler and have higher PART II RH levels than the living space above. D. If an unfinished basement becomes finished, the Basements conditions below the floor will change, which The floor of a building that is partly or entirely below- could affect an already installed wood floor. grade. Basements are normally constructed to keep both liquid and capillary water from finding its way into the structure. This is often done by using vapor barriers PART III on the foundation walls, surface drainage systems, below-grade drainage systems, perimeter drainage Crawlspaces systems, and capillary breaks. The floor of the house is built over an open space that A. The ambient conditions of the basement will is deep enough to allow a person to gain access to the change from season to season and may affect under-floor area by crawling. the flooring above. A. Structural Requirements of a Crawlspace:
1. The distance from the earth to the underside B. In a finished basement, the walls are normally of the floor joist must be a minimum of 18” insulated, and the space is heated and cooled and a minimum of 12” from the earth to the similarly to the above living space. This is underside of the beams. considered a conditioned space.
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2. Piers/Stilts: The pier should be set on the 2. V entilated Crawlspaces: The International footing evenly. Residential Code (IRC), section R408, contains B. T emperature and moisture conditions in the a standard requirement for ventilation in crawlspace: crawlspaces. 1. In general, unconditioned crawlspaces are a. The underfloor space between the bottom cooler and have higher relative humidity of the floor joists and the earth under levels than in the living space above. any building (except space occupied by a basement) shall have ventilation openings 2. Humidity levels in crawlspaces are elevated through foundation walls or exterior walls. by the evaporation of moisture from the soil. Evaporation generally is greatest during summer, when the soil is warmer, and less during the winter, when it is cooler. A Class I vapor retarder installed over the ground greatly reduces evaporation from crawl space floors, thereby lowering crawl space humidity levels. 3. The temperature gradient from the cooler underside of the subfloor system in the crawlspace to the indoor living side of the subfloor system can be drastic. This temperature gradient may result in condensation forming on the underside of the subflooring due to the dew point. C. A crawlspace can be classified into three general categories: b. The minimum net area of ventilation openings shall not be less than 1 square foot (0.0929 square meters) for each 150 square feet (14 square meters) of under-floor space area, unless the ground surface is covered by a Class I vapor retarder material.
1. Open Crawlspaces: Open pier-and-beam foundations are considered open crawl spaces. These are considered unconditioned spaces. a. Open crawl spaces may have a continuous wall on just one side and be open on the other sides. b. Skirting these types of crawl spaces to form an enclosed crawl space and then c. Where a Class I vapor retarder material adding venting could result in moisture is used, the minimum net area of issues, especially in hot and humid areas ventilation openings shall not be less of the country. than 1 square foot (0.0929 square meters) for each 1,500 square feet (140 square meters) of under-floor space area. d. One such ventilating opening shall be within 3 feet (914 mm) of each corner of the building.
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iv. Dehumidific ation sized to provide 70 pints (33 liters) of moisture removal per day for every 1,000 square feet (93 square meters) of crawlspace floor area. 4. Vapor retarder installed on the underside of the joists: According to IRC section R408.8, in hot and humid climates (specifically climate zones 1A, 2A, and 3A below the warm humid line), it is a standard requirement for the builder to provide installation of a continuous Class I or Class II vapor retarder to be installed on the exposed face of air-permeable insulation installed between the floor joists, 3. Enclo sed and Conditioned Crawlspaces: Crawl and exposed to the grade in the under-floor spaces are considered enclosed and conditioned space. This vapor retarder shall not be where they meet all requirements as detailed required in unvented crawlspaces constructed in IRC section R408.3, and the entire space in accordance with the IRC Section R408.3. is conditioned and maintained at the same temperature and humidity levels as the above interior living space. These crawl spaces present the ideal circumstances to create a balanced condition below and above the flooring system. IRC section R408.3, ventilation openings in crawlspaces shall not be required where the following items are provided: a. Exposed earth is covered with a continuous Class I vapor retarder. Joints of the vapor retarder shall overlap by 6” (152 mm) and shall be sealed or taped. The edges of the vapor retarder shall extend not less than 6” (152 mm) up the D. Crawlspace Insulation: stem wall and shall be attached and sealed 1. In unconditioned spaces such as open and to the stem wall or insulation; and ventilated crawlspaces, insulation plays an b. One of the following is provided for the important role in the temperature gradient crawlspace: and moisture migration from an unconditioned i. C ontinuously operated mechanical space into a conditioned space. Insulation exhaust ventilation at a rate equal installation should be completed by a qualified to 1 cubic foot per minute (0.47 L/s) professional. for each 50 square feet (4.7 square 2. Building codes in many climate zone regions meters) of crawlspace floor area, dictate construction methods related to including an air pathway to the insulation and moisture control systems common area (such as a duct or installed in crawlspaces. transfer grill), and perimeter walls 3. Common insulation and vapor retarding insulated in accordance with Section systems used below the subfloor include N1102.2.22 of IRC, or fiberglass batt insulation, closed-cell spray ii. C onditioned air supply sized to foam insulation, and foil-faced rigid insulation deliver at a rate of equal to 1 cubic panels. foot per minute (0.47 L/s) for each 50 square feet (4.7 square meters) of crawlspace floor area, including a return air pathway to the common area (such as a duct or transfer grill), and perimeter walls insulated in accordance with Section N1102.2.22 of IRC, or iii. Plenum in existing structures complying with Section M1601.5 of IRC, if the crawlspace is used as a plenum, or
© 2019 NATIONAL WOOD FLOORING ASSOCIATION 47 NATIONAL WOOD FLOORING ASSOCIATION TECHNICAL PUBLICATION SUBSTRATES: Wood Subfloors
Wood flooring by design is not to be used to strengthen/stiffen a subfloor and will not do so. The subfloor is the foundation for the wood floor. The final wood floor installation is only as good as the subfloor it is installed over. With new construction, it is the responsibility of the builder to ensure the facility is designed and capable of sustaining an environment conducive to the building materials being used in it. The wood flooring contractor shall not be responsible for the design or installation of the subfloor system, inadequate deflection limits, improper joist/floor truss spans, and spacing/panel thickness combinations, or any subsequent flooring problems resulting from prior jobsite damage, unless otherwise contracted to do so. If it is the opinion of the wood flooring contractor that the subfloor is not in suitable condition for hardwood flooring, it is the responsibility of the wood flooring contractor to either remedy the subfloor and/or to notify the builder/owner prior to installation to allow them to make it suitable for the flooring being installed.
PART I Floor Joists and Trusses Floor joists and trusses are the structural components in a floor framing system that transfer floor loading above to the wall or foundation-bearing supports below. They run between foundations, walls, or beams, and typically are laid out in repetitive patterns. They can be made of solid wood, engineered wood, or steel. You can work with the architect, the builder, and the designer to ensure the facility is designed and capable of maintaining the minimum requirements necessary for the flooring products being used in it. B. I-jois ts have a higher strength-to-weight ratio than lumber joists and often are used for longer spans. They use top and bottom flanges that typically are solid lumber, structural composite lumber, or laminated veneer lumber (also called LVL). They also use web material that typically is made of oriented strand board (OSB).
A. Traditional lumber joists are usually 2”x or 3”x dimensional material and are sized according to the these factors: 1. Species and grade of the wood. 2. Spacing and span of the joists. C. Floor trusses usually are made up of 2”x4” or 3. The design load requirements. 2”x3” lumber on top and bottom chords with an open-web configuration with metal plates. The lumber in the floor truss flanges usually is oriented flat-wise providing for up to 3½ ” wide bearing surfaces. These trusses are often used for longer spans than lumber joists.
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D. Maximum subfloor deflection limits are set by 1. Plywood subfloor panels should conform building codes. They are expressed as a fraction: to the most-current U.S. Voluntary Product clear span in inches (L) over a given number. Standard PS 1 performance standard, for Building code allows for the maximum allowable Construction and Industrial Plywood and/or floor member live load and concentrated load Canadian standards CSA 0153 or CSA 0121, deflection for wood framed floor systems to not and/or Canadian performance standard exceed L/360, where “L” is the clear span length CAN 0325. It should also comply with the of the supporting members. requirements of the International Residential 1. A subfloor system built to this minimum Code (IRC) and International Building Code specification is sufficient for most wood floor (IBC) at the date it was manufactured. installations. 2. Some thinner-profile (solid and engineered) wood flooring products may benefit from a stiffer subfloor system. 3. Subflooring systems that lack adequate stiffness can contribute to performance problems in wood floors such as fasteners pulling out of the subfloor, excessive noise, and potential damage to the surface finish. Where subfloor deflection is a concern, a qualified professional can help the end-user determine the best method to stiffen the subfloor system. Some common options for stiffening a subfloor system include: a. Increasing the subfloor panel thickness. b. A dding a second layer of wood panel 2. Oriented strand board (OSB) subfloor subflooring to the existing subfloor. panels should conform to the governing c. S electing a high-performance subfloor version U.S. Voluntary PS 2 and/or Canadian product that has a higher design stiffness performance standard CAN/CSA 0325 or than commodity panel options. CSA 0437. It should also comply with the d. Incr easing the depth of the floor joists/ requirements of the IRC and the IBC at the trusses. date it was manufactured. e. S electing a wood grade for the floor 3. Some manufacturers have chosen to joists/trusses with a higher modulus produce wood structural panels that have of elasticity. higher strength, stiffness and fastener f. Reducing the floor joist/truss spacing. holding properties than commodity OSB g. R educing the span of the floor joists/ and plywood subflooring. To be recognized trusses as “high-performance” subflooring, panels must have an accompanying evaluation report from an approved testing agency PART II substantiating any claims to elevated performance properties. Enhanced Wood Panel Subflooring performance properties shall be listed in A. Wood Panel Subfloor Standards: the evaluation report. Proprietary reports typically list these properties as “design values” to be used by specifiers. 4. These standards apply to wood structural panels suitable for use as subflooring material, which should be plywood or oriented strand board with a bond classification of Exposure 1 or Exterior. Alternative wood-based structural panels are permitted if recognized in a current Evaluation Report from an approved testing source as satisfying the requirements for subflooring in the governing building code.
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B. Wood Panel Subfloor Identification: 1. When possible, check the back of the subfloor panel for identifying information about the panel such as span rating, thickness, and exposure rating. This information is listed within the third party certifying agency stamp. Flooring assemblies (joist/floor truss spacing and panel thickness) must be designed and constructed to accommodate design loads and the floor covering being installed over it. 2. When evaluating the wood panel subfloor, the underside of the installed panel should contain a product grade stamp from an accredited testing agency indicating that is complies with the governing product standard (PS 1 or PS 2) at the time it was manufactured. Common accredited testing agencies for OSB and plywood subfloors are APA (The Engineered Wood Association), PFS TECO (PFS Corporation and Timberco Inc.), and TPI (Timber Products Inspection). The information included in each of these stamps is detailed here:
Panel Grade
Span Rating
Bond Classification
Mill-Thickness
Mill Number
Reference Standards
Performance Category Mill Number
Reference Standards
Reference Standards Bond Classification
Bond Classification Performance Category
Performance Category Span Rating
Span Rating
Mill-Thickness Mill-Thickness
Panel grade: identifies the intended Bond classification: indicates Mill number: Identifies the Mill ID #. use of the panel. how much weather and moisture Reference standards: industry Span rating: maximum for roof the panel is designed to withstand. standard designations. spans/maximum for floor joist span. Mill-thickness: thickness of the Performance category: nominal material. thickness of product.
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PART III Wood Panel Performance Category for Plywood or OSB Wood Panel Subfloor PERFORMANCE CATEGORY MILL THICKNESS (NOMINAL THICKNESS) LABEL Installation Requirements 1/4 0.225 in. (5.715 mm) A. Single floor subfloor panels should be installed continuous over two or more spans, with the long 11/32 0.322 in. (8.179 mm) panel dimension (strength axis) perpendicular 3/8 0.354 in. (8.992 mm) to floor trusses or joists. All panel edges not 7/16 0.418 in. (10.617 mm) supported continuously with framing shall be tongue and groove. 15/32 0.451 in. (11.455 mm) B. To minimize the potential for floor squeaks, most 1/2 0.483 in. (12.268 mm) wood panel subfloor manufacturers recommend 19/32 0.578 in. (14.681 mm) that the subfloor panels be glued and nailed to 5/8 0.609 in. (15.469 mm) the floor framing using recommended fasteners and subfloor adhesives conforming to ASTM 23/32 0.703 in. (17.856 mm) D3498 or APA Specification AFG-01. Joist spacing 3/4 0.734 in. (18.644 mm) greater than 16” on center (O.C.) must be glued 13/16 0.788 in. (20.015 mm) and fastened. A thin bead of glue inside the groove profile is also sometimes recommended. 7/8 0.849 in. (21.565 mm) C. The ends of the panels should land at the center of 1 0.970 in. (24.638 mm) the floor joist/truss, with a minimum bearing of ½ ”. 1-1/8 1.091 in. (27.711 mm) D. Glue-nailed subfloor panels up to 23/32” thick 1-1/4 1.213 in. (30.810 mm) should be fastened with 6d ring- or screw-shank nails, 8d common nails, or proprietary screws spaced 12” O.C. along panel edges and 12” O.C. along intermediate supports. Some subfloor panel manufacturers may have more-restrictive fastener requirements. E. Typical panel edge spacing requirements for floor joist/truss systems call for 1/16” - 1/8” gap around the perimeter (all four sides) of each panel. Some panel manufacturers mill their tongue and groove edges to gap themselves. NOTICE: For additional information on the installation of Wood Panel Subflooring, see APA’s Engineered Wood Construction Guide (Form E30) at www.apawood.org or refer to the panel manufacturer’s recommendations.
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Joist/Floor Truss Spacing & Panel Thickness Requirements for Wood Flooring Installation
NWFA WOOD SUBFLOORS ≤16” JOIST SPACING 111 CHESTERFIELD INDUSTRIAL BLVD. CHESTERFIELD, MO 19/32" PLYWOOD OR 23/32" 63005 OSB 1 8"
1 2"
ENDS OF THE PANELS MUST LAND AT THE CENTER OF THE FLOOR JOIST/TRUSS, 1 WITH A MINIMUM BEARING 2"
JOIST/TRUSS WOOD SUBFLOORS ≤16" JOIST SPACING FLOOR SYSTEMS:
<16" ℄ SPACING <16" ℄ SPACING REV. BY: DATE:
1 - - NOTE: JOISTWHERE MINIMUM BUILDINGMINIMUM CODE SUBFLOOR IS LESS PANEL 2 - - SPACING RESTRICTIVE THANPERFORMANCE NWFA CATEGORY RECOMMENDATIONS, THE EXISTING ≤16” (406 SUBFLOORmm) WILL REQUIRE19/32 INSTALLATIONplywood or 23/32 OSB OF A DOUBLE-LAYER SUBFLOOR SYSTEM. DRAWN BY: DATE: HD 9-23-19
SECTION: WOOD SUBFLOORS ≤16" JOIST SPACING SHEET# 1 SCALE: 3"=1'-0"WOOD SUBFLOOR >16” & ≤19.2” JOIST SPACING 1 SUBFLOOR PAN L FAST N RS SPAC D 1 " O C ALONG PAN L DG AND 1 " O C ALONG INT R IDIAT SUPPORTS NWFA 111 C ST RFI LD INDUSTRIAL BL D " PL WOOD OR OSB C ST RFI LD O 6 1 8"
1 "