DOCSLIB.ORG

Crawl Spaces in the Home

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Crawl Spaces in the Home Craw-l Spaces in the Hotne Council Notef4.4 Building Research Council School of Architecture University of Illinois at Urbana-Champaign Crawl Spaces in the Home spection purposes and to service equip­ CRAWL SPACE CONSTRUCTION Crawl space houses should ment, such as a sump pump or furnace. Many houses without basements are and can be constructed so built over crawl spaces. That is, the floor that they are free from the of a house is built over an excavation MOISTURE SYMPTOMS AND SOURCES deep enough for someone to gain access Obvious symptoms of excessive moisture problems of moisture. to the underfloor space by crawling. The passing up through the floors and walls in­ minimum depth of the crawl space clude: should be 24 inches under the floor joists, A a musty odor; mold on the walls near the or 18 inches under any beams or sup­ floor, in corners, and in closets; ports. An 18-inch clearance beneath duct A moisture condensation on windows work is also desirable. which are equipped with insulating glass or storm windows; A moisture or frost on the underside of roof sheathing; and A peeling paint on walls with moisture condensation. In the crawl space itself, moisture prob- lems may be indicated by: Repair and modernization A toadstools or furry mats on lumber; problems are simpler in A damp earth; crawl-space houses than in a house with a slab foundation. A mold on the ground; A condensation on masonry foundation walls; and A mildew or condensation on band joists and subfloor. These are more likely to appear along the north side of the house. The exterior walls of the house and the outer edges of the floor framing com­ Sometimes there are no visible symp­ monly rest on a foundation wall extend­ toms of moisture problems within the ing around the house. Sometimes, how­ crawl space itself. ever, the exterior walls and the floor are The only satisfactory way to avoid supported by beams that rest on piers lo­ moisture problems is to prevent moisture cated around the edge of the house. In from entering the crawl space. Moisture such construction, non-load-bearing problems that show up within a house as condensation or frost on the underside of The information contained in this skirting usually encloses the crawl space roof sheathing, or as condensation or publication was produced by the excavation. School of Architecture-Building The interior ends of floor joists are gen­ frost on windows in the living area may Research Council (BRC) at the erally supported on wood or steel beams be the result of dampness in the crawl University of Illinois at Urbana­ that rest on masonry or concrete piers, space. An uncorrected moisture problem Champaign. For a set of 27 but support can be provided by load­ can cause decay of the wood-floor fram­ Council Notes for $29.95 call bearing walls. ing and ultimately structural failure of 1-800-336-0616. Floors overhead are usually of wood the house. with conventional joist construction. Moisture problems in crawl spaces may be However, concrete, masonry, metal, or a due to: combination of these materials can be A the construction of a crawl space in an used. Normally, the crawl space contains area of high water tables; only plumbing pipes, heating and cool­ A improper grading of the lot for drain - ing ducts or pipes, and electrical wiring. age; or Easy access should be provided for in- A the absence of moisture control devices such as a ground cover or ventilation openings. Crawl space houses should and can be constructed so that they are free from the problems of moisture, they resist termite 2 Building Research Council infestation, and the floor and rooms pressure against the crawl-space walls. above the crawl space can be kept at Rainwater falling on the ground or from comfortable temperatures with a mini­ the roof can pass through or under the mum of heat loss from the structure. foundation walls. To avoid such prob­ lems, grade the lot so that drainage runs Ground Water away from the house and no water is al­ Sometimes the level of the water in the lowed to stand on the site. ground (water table) is raised above the Minimum grading specifications will suf­ bottom surface of the crawl space. fice for most conditions: Water may penetrate the foundation A the slope of the grade should be at least walls or rise through the ground surface 6 inches in 10 feet; in the crawl space, allowing water to A the ground should fall at least 6 inches stand in the crawl space. on all sides of the house; and This is commonly due to: A the slope should extend at least 10 feet A heavy or prolonged rains; out from the foundation, except where A a spring which appears during wet sea - side yards are narrower. sons only and was not discovered when In new construction, it will usually be the house was built; necessary to provide additional fill next A water flowing along an impervious layer to the house the first year or two after within the soil; or construction to compensate for the set­ A an overlooked farm drain tile. tling of the backfill around the founda­ Crawl space construction is not recom­ tion. Failure to do so may result in a mended if the ground-water level in the "moat" around the house. area is so high that it can flood the crawl To divert rainwater, use wide over­ space periodically. hangs and/ or gutters and downspouts Where a spring or drain tile is discovered extending several feet from the house. after construction, or where unexpected Where gravel beds are used as a drip flooding occurs: area substituting for gutters, the ground A detour the drain around the house; level is really at the bottom of the gravel A install a footing tile around the outside of and the grading must be done so that the crawl space at foundation level with water drains from the bottom of the the bottom of the footing; gravel bed. Make sure that downspout A backfill with coarse gravel to within 8 extenders or splash blocks are used to inches of the finished grade; discharge rainwater past the backfill onto Dampness within a crawl space A install field tile or perforated plastic the undisturbed soil. In a crawl space can usually be avoided if the lot drain lines within the crawl space; house, this is usually 2 feet to 3 feet away is graded correctly and a A grade the bottom of the crawl space so from the foundation. Do not connect moisture-control device, such as a that any water will drain to the tile; downspouts to footing drains. plastic ground cover, is used. In areas of high water tables, install a A cover the crawl space area with coarse gravel (fine gravel or sand tends to footing drain or field tile with open joints block tile); and or perforated plastic drainage tubing. Connect the tile to a sump pump, or to A provide either a gravity drain or sump pump to remove the water collected by "daylight." Waterproof the outside walls the drainage lines. with a bituminous coating. Costs and installation problems inhibit Capillary Rise of Ground Moisture the use of other effective methods of Moisture travels upward from lower lay­ groundwater control, such as a mem­ ers of certain soils by capillary action and brane waterproofing system. evaporates within the crawl space (as Surface Water much as 13 gallons per day have been noted to rise under a 1,000 square foot Surface drainage problems usually occur house). Capillary rise occurs in nearly all because the floor of the crawl space is crawl spaces built in areas where the soil two to three feet below the finish grade is composed of clay or silt. The moisture outside the house. Heavy soils may re­ is present even though the ground in the tain surface drainage and create water 3 Crawl Spaces in the Home crawl space may seem dry, dusty, and Provide at least four corrosion-resistant even cracked. foundation vents that can be closed dur­ Moisture from capillary rise can be ing the heating season and during humid kept out of the crawl space by using a summers. The bottom of the vent open­ vapor-retarding ground cover that is not ing should be at least 2 inches above the susceptible to damage by fungi. Polyeth­ soil grade to prevent rainwater from en­ ylene film, 6 mils thick is effective. To in­ tering the crawl space through the vent. stall this, grade and smooth the ground, Insulated covers should be cut from and remove any trash or debris. Turn up panels of rigid foam insulation. The vent the ground cover four to six inches on the openings should be screened with eight­ wall of the crawl space. Hold the poly­ by-eight corrosion-resistant mesh (64 ethylene in place against the walls with openings per square inch) to keep out in­ sand or bricks to help achieve a neat in­ sects. If the crawl space is dry, opening stallation. Where more than one piece of the vents may not be necessary, even in polyethylene is needed, lap the edges the summer; but it is much easier to four to six inches. Sealing the edges is not block and insulate vents that were not necessary. Use wide rolls of polyethylene needed than to install vents that were not to reduce the number of edge joints. originally provided. Open Crawl Space Moisture From Mechanical Systems Open Crawl Spaces O ften moisture is introduced into the O pen crawl spaces are those that are crawl space from the mechanical systems ventilated to such an extent that the tem­ within the home.
Load more

Recommended publications
  • Crawl Space Encapsulation Plan Review and Inspection Requirements
    M E M O R A N D U M Date: June 16, 2017 To: Crawl Space Encapsulation Installers From : Karolee Towe, Plan Review Chief Building Safety & Permits Subject: Crawl Space Encapsulation Plan Review and Inspection Requirements Crawl Space Encapsulation N1102.2.10 (R402.2.10) Crawl space walls. As an alternative to insulating floors over crawl spaces, crawl space walls shall be permitted to be insulated when the crawl space is not vented to the outside. Crawl space wall insulation shall be permanently fastened to the wall and extend downward from the floor to the finished grade level and then vertically and/or horizontally for at least an additional 24 inches (610 mm). Exposed earth in unvented crawl space foundations shall be covered with a continuous Class I vapor retarder in accordance with this code. All joints of the vapor retarder shall overlap by 6 inches (153 mm) and be sealed or taped. The edges of the vapor retarder shall extend at least 6 inches (153 mm) up the stem wall and shall be attached to the stem wall. Mechanical Ventilation To comply with this provision, the crawl space must be mechanically vented or supplied with conditioned air from the living space. One of the following must be provided: • Continuously operated mechanical exhaust ventilation at a rate equal to 1 cubic foot per minute (0.47 L/s) for each 50 square feet (4.7m 2) of crawlspace floor area, including an air pathway to the common area (such as a duct or transfer grille), and perimeter walls insulated in accordance with Section N1102.2.10.
    [Show full text]
  • Building Products BUILDING PRODUCTS Anchor Bolts
    MARCH 2012 BBUUIILLDDIINNGG PPRROODDUUCCTTSS TS PRODUC -MADE ERICAN ING AM 1946 PRODUC SINCE Vestal Manufacturing Enterprises, Inc. P.O. Box 420 • Sweetwater, Tennessee 37874 (423) 337-6125 • USA WATS 1-800-456-9562 Fax 423-337-2003 [email protected] • www.vestalmfg.com Building Products BUILDING PRODUCTS Anchor Bolts . BP-18 Ash Caddy . BP-10 Ash Dumps . BP-10 Basement Columns . BP-19, BP-20, BP-21 Bell Traps . BP-28 Brick Clamp . BP-16 Brick Vents . BP-15 Cesspool Plates . BP-28 Chimney Caps . BP-6 Chimney Top Dampers . BP-6 Circulator Duct System . BP-2 Circulator Fans . BP-3 Circulator Fireplaces . BP-1 Circulator Grilles . BP-2 Cleanout Doors . BP-11 Crawlspace Doors . BP-15 Dampers . BP-8, BP-9 Damper Controls . BP-7 Dutch Oven Door . BP-26 Fire Bricks . BP-5 Fire Clay & Heat Stop . BP-5 Flue Liners . BP-5 Foundation Anchors . BP-18 Foundation Galvanized Flood Vent . BP-14 Foundation Vents . BP-12, BP-13, BP-14 Frames and Covers . BP-27 Galvanized Brick Lintel . BP-22 Hearth Pans . BP-7 Lintels . BP-22, BP-23 Metal Lath . BP-16 Mortar Boxes and Tubs . BP-17 Multi-Opening Damper Corner Supports . BP-9 Outdoor Barbecue Grilles . BP-26 Outdoor Barbecue Grates . BP-26 Outside Air Kits . BP-4 Posts . BP-19, BP-20, BP-21 Post Parts . BP-19 Rebar Chairs . BP-18 Spigot Grate . BP-28 Steel Angle . BP-23, BP-24, BP-25, BP-26 Tile Strainers . BP-28 Trench Drains . BP-28 Tube-Aire Rotary Control . BP-1 Wall Ties . BP-17 Window Wells .
    [Show full text]
  • Conditioned Crawl Space Construction, Performance and Codes
    building science.com © 2006 Building Science Press All rights of reproduction in any form reserved. Conditioned Crawl Space Construction, Performance and Codes Research Report - 0401 2004-11-02 by Joseph Lstiburek, Building Science Corporation Abstract: Conditioned crawl spaces perform better than vented crawl spaces in terms of safety, health, comfort, durability and energy consumption. Conditioned crawl spaces also do not cost more to construct than vented crawl spaces. Existing vented crawl spaces are experiencing serious moisture and mold problems and are costing builders and homeowners significant resources to repair. Despite the obvious problems with existing vented crawl spaces and the obvious benefits of conditioned crawl spaces there is not a significant trend towards the construction of conditioned crawlspaces. One of the reasons typically cited by builders and designers is “the code does not allow me to build unvented crawl spaces”. This is both generally correct and misleading. The model codes do not allow the construction of “unvented” crawl spaces – except in very limited circumstances, but they do allow the construction of “conditioned” crawl spaces. The distinction is important and necessary. Four conditioned crawl spaces were constructed and monitored over a 12-month period. The data is presented and used to support the current code requirements for the construction of conditioned crawl spaces. BUILDING AMERICA SYSTEMS ENGINEERING APPROACH TO DEVELOPMENT OF ADVANCED RESIDENTIAL BUILDINGS 5.C.2.4 CONDITIONED CRAWL SPACE CONSTRUCTION, PERFORMANCE AND CODES RE:TASK ORDER NO. KAAX-3-32443-4, 5, AND 6 UNDER TASK ORDERING AGREEMENT NO. KAR-8-18412-00 MIDWEST RESEARCH INSTITUTE, NATIONAL RENEWABLE ENERGY LABORATORY DIVISION, 1617 COLE BOULEVARD, GOLDEN, CO 80401-3393 BUILDING SCIENCE CONSORTIUM CONSORTIUM LEADER: BUILDING SCIENCE CORPORATION 70 MAIN STREET, WESTFORD, MA (978) 589-5100 CONTACT: BETSY PETTIT, AIA CONSORTIUM MEMBERS: PULTE/DEL WEBB CORPORATION DAVID WEEKLEY HOMES ARTISTIC HOMES CENTEX HOMES TECHNICAL OLYMPIC APRIL-AIRE, INC.
    [Show full text]
  • 2018 Crawl Space Information
    Knox County Code Administration & Inspection IRC – Under-Floor Space Information REV. 022019 SECTION R408 UNDER – FLOOR SPACE (Partial readings of code section) R408.1 Ventilation The under-floor space between the bottom of the floor joists and the earth under any Building Foundation building (except such space occupied by a basement) shall have ventilation openings through foundation walls or exterior walls. The minimum net area of ventilation openings shall not be less than 1 square foot for each 150 square feet of crawl space area, unless the ground surface is covered by a class 1 vapor retarder material. Where an approved vapor retarder is used, the minimum ventilation shall be 1 square foot of ventilation per Crawl Space Vent 1500 square feet of under floor space area. One such ventilating opening shall be within (typ.) 3 feet of each corner of the building. R408.2 Openings for Under-floor Ventilation Ventilation openings shall be covered for their height and width with any of the following One vent within 3 materials provided that the least dimension of the covering shall not exceed ¼”. Foundation Vent Layout feet of building 1. Perforated sheet metal plates not less than 0.070inch thick. corner 2. Expanded sheet metal plates not less than 0.047 inch thick. 3. Cast iron grill or grating. 4. Extruded load bearing brick vents. 5. Hardware cloth of 0.035 inch wire or heavier. Foundation wall 6. Corrosion Resistant wire mesh, with the least dimension being 1/8 inch. R408.3 Unvented Crawl Space (Requires approval of submitted plans) Ventilation openings are required where one of the following are provided: Note: Vents 1.
    [Show full text]
  • Actions You Can Take to Protect a Flood-Prone House Or Business
    Actions You Can Take to Protect a Flood-Prone House or Business with a Crawlspace If your home or business has been flooded or is located in or near a flood hazard area, you typically have two choices: 1. Wait for the government to do something, like construct a reservoir or levee, or 2. Take actions on your own to reduce your risk of flood damage. This brochure is for homeowners and business owners who want to reduce their exposure to flood damage (and potentially lower flood insurance premiums). Even if a government agency is planning to construct a reservoir or other flood control project, it may take years before it is constructed and operational. Meanwhile, you may flood again. This brochure provides a step-by-step decision-making process that can help you to reduce flood risk. While it is advisable to consult with your local floodplain management administrator on regulatory and flood insurance requirements, this brochure is intended to provide basic flood risk reduction advice for structures located on a crawlspace. Step 1. Learn About Your Flood Hazard You may have been flooded in the past, but the next flood could be worse. Talk to your community’s floodplain management, planning, engineering or permit office and review any flood or drainage studies that have been done for your area. Answer these questions: a. How deep have past floods been? Don’t assume the last flood is the worst that can happen. You also need to answer the following questions. b. How deep could a future flood be? While your community staff won’t be able to make a prediction, they should have a Flood Insurance Rate Map and a Flood Insurance Study (FIS) that could tell you how deep different floods could be.
    [Show full text]
  • RH-12 - 1 May 2003 ACTIVITY: Tips for Wet Basements and Crawl Spaces RH – 12
    ACTIVITY: Tips for Wet Basements and Crawl Spaces RH – 12 WET BASEMENT AND CRAWL SPACE PROBLEMS, CAUSES AND REMEDIES -- TIPS FOR HOMEOWNERS AND HOME BUYERS The primary purpose of this BMP is to inform the homeowner, home buyer, and home builder about the usual causes for wet basements and crawl spaces, plus effective measures for preventing or correcting problems. This information can enable the public to build, select, or repair homes wisely. Although this BMP is not directly connected with water quality and stormwater pollution, the matter of wet basements and crawl spaces is closely related to stormwater design, This BMP is adapted from a booklet landscaping, and minimizing contact with stormwater. (original date - September 1997) by: Dr. Bruce A. Tschantz, P.E. UT Water Resources Research Center University Of Tennessee, Knoxville Immediate & Long-Term Problems Causes of Wet Basements and Crawl Spaces Preventing Wet Basements and Crawl Spaces Tips for Homeowners and Home IMMEDIATEBuilders AND LONG-TERM PROBLEMS Standing water or seepage inside residential crawl spaces and basements can cause frustrating problems for the homeowner. These problems can be both immediate and long-term. For example, standing water and mud inside crawl spaces make it very difficult and messy to gain access under the house for inspecting, maintaining, and servicing electrical circuits, drains and water lines, heating and air conditioning, and other utilities. Wet basements and crawl spaces are sources of high humidity, which can produce surface condensation, mildew and fungi, musty odors, and an unhealthly environment. Such moisture can cause deterioration of floor joists, beams, subflooring, insulation, and electrical-mechanical systems.
    [Show full text]
  • Severe Storm Protection
    Severe Storm Protection: NOTES: 1. SPACE REQUIREDTER INSIDE IS MIN. 2" DIA. TION PIPE Regulation Guidance for Local Governments IN-GROUNDF./ PERSON, SHEL LARGER VENTILA MIN. 5 S. 2'-6" X 2'-6" ACTURERS FOR HATCH NOS. & MANUF ENTRY 2. MODEL HATCH COVERS INCLUDE: MODEL NO. ACTURER T MANUF A150 TCH EITHERT CAS ACCESS HA #5 BARS ACUDOR F L INTO MH. LID OR CAS @6" O.C.-IN-PLACE BOTH DIRECTIONS LID INTO FLOOR SLAB - SEE NOTE 2 IN CAST BILCO J4A DRAWING IG-1 THROUGH T AWAY FROM VIS FB4700 AIRHOLES DRILLEDL AT LEAS SLOPE FLOOR T BABCOCK-DA HATCH LID DRIL MH. LID ORO PREVENT CONSTRUC (25) 1 / 2" DIA. HOLESTCH IN LEDGE T AMILIAR WITH THE TYPE WATER CTORS ARE F WINGS, THE NAMESVE OF THE ACCESS HA RY OF NOTES: VERS HA ENT USE NOT ALL CONTRAWN IN THESE DRA TCH CO BECA VER SHO FACTURE HA ANIES IS CONC. OF HATCH CO T MANU PRECAST ANIES THA , THIS LIST IS NOT PIPE 2 SOME COMP ABLE. THE LIST OFLY COMP SHELTER LID TION UDED IN THIS T CLAMP BEEN INCL USTIVE. ADDITIONAL 8" TIVE LOCA WEVER, EXHA ALTERNA LY AVAILABLE NOT, HO ODUCTS BY THE UNITED INTENDED TO EXPRESS A PREFERENCE FOR THOSE COMMERCIAL CTURERS AND/OR THEIR PR SCREENING MANUFA S. SCREENING RODENT VERNMENT NOR IS IT AN ENDORSEMENTODUCT OF THOSE INSECT AIL STATES GO CTURERS AND/OR THEIR PR WRAPPED OVER LADDER RUNGS LADDER OR SEE DET 1 MANUFA FULL HEIGHT IG-1 END OF PIPE T PRECAS CONC. #5 BARS BOX 8'-0" @6" O.C.
    [Show full text]
  • Floors Above Crawl Spaces: Reducing the Risk of Moisture Accumulation Within Wood Floor Assemblies 3 Building Code
    Floors above Crawl Spaces: Reducing the Risk of TechNote Moisture Accumulation within Wood Floor Assemblies For Residential Buildings in Hot-Humid Climates Floors above vented and open crawl spaces in hot-humid climates are susceptible to moisture CRAWL SPACE FOUNDATION TYPES accumulation that could lead to mold, mildew, and decay within the floor assembly, even Vented (traditional) crawl space: a crawl where crawl spaces are constructed in accordance with building codes. space with a continuous perimeter Water vapor generally migrates from areas of higher temperature and relative humidity to foundation wall (typically masonry) with ventilation openings to the outdoors areas of lower temperature and relative humidity (vapor drive). In a humid climate, during intended to control crawl space humidity. the cooling season, the vapor drive is from the crawl space to the relatively cool and dry indoors through the floor assembly. A vapor impermeable floor covering can trap moisture Open crawl space: a crawl space where in the wood subfloor Conditions within the crawl space can lead to condensation and high individual piers (typically wood, masonry, or concrete) at the building perimeter wood moisture content (see Figure 1 and Figure 2). support beams and floor joists. This TechNote provides design recommendations to reduce the risk of moisture accumulation Unvented (sealed, closed, or within wood floors above crawlspaces in hot-humid climates – IECC climate zones 1A, 2A, conditioned) crawl space: a crawl space and lower portions of 3A below the warm-humid line [1]. The factors that affect moisture with a continuous perimeter foundation accumulation include season, indoor temperature, types of floor insulation and floor covering, wall that is sealed (no wall vents) to and type of crawl space (see sidebar).
    [Show full text]
  • Sealed Crawl Space with Integrated Whole-House Ventilation in a Cold
    Technology Solutions for New and Existing Homes Building America Case Study Sealed Crawl Spaces with Integrated Whole-House Ventilation in a Cold Climate Ithaca, New York One method of code compliance for crawl spaces is to seal and insulate the PROJECT INFORMATION crawl space rather than vent to the outdoors. However, codes require mechanical Project Name: Holly Creek Townhouses ventilation (International Residential Code [IRC] Section R408.3), either via con- Location: Ithaca, NY ditioned supply air from the space-conditioning system or a continuous exhaust Partners: ventilation strategy. Ithaca Neighborhood Housing Services is a builder partner of Ithaca Neighborhood Housing Services, the U.S. Department of Energy Building America team, Consortium for Advanced ithacanhs.org Residential Buildings (CARB). This partner intended to use the unvented crawl Consortium for Advanced Residential space in a recent development. In support of this project, CARB investigated a Buildings, carb-swa.com hybrid ventilation method that included the exhaust air from the crawl space as Building Component: Ventilation, part of an ASHRAE 62.2-compliant whole-house ventilation strategy. sealed crawl space Application: New and/or retrofit; The CARB team evaluated this hybrid ventilation method through long-term single- and multifamily field monitoring of temperature, humidity, and pressure conditions within the Year Tested: 2014–2015 crawl spaces of two homes (one occupied and one unoccupied) in New York Climate Zones: Cold (5–6) state. CARB also worked with the National Renewable Energy Laboratory to perform multipoint tracer gas testing on six separate ventilation strategies, PERFORMANCE DATA varying parts of ASHRAE 62.2-required flow supplied by the crawl space fan Sealed crawl spaces can: and an upstairs bathroom exhaust fan.
    [Show full text]
  • Conditioned Crawl Space Guide
    Abstract CONDITIONED Conditioned crawl spaces perform better than vented crawl spaces in terms of safety, health, comfort, durability and energy consumption. Conditioned crawl spaces also do CRAWL SPACE not cost more to construct than vented crawl spaces. Existing vented crawl spaces are experiencing serious moisture and mold problems and are costing builder’s and homeowners significant resources to repair. Despite the PERMIT GUIDE obvious problems with existing vented crawl spaces and the obvious benefits of conditioned crawl spaces there is not a significant trend towards the construction of conditioned crawlspaces. One of the reasons typically cited by builders and designers is “the code does not allow me to build unvented crawl spaces”. This is both generally correct and misleading. The model codes do not allow the construction of “unvented” crawl spaces – except in very limited circumstances, but they do allow the construction of “conditioned” crawl spaces. The distinction is important and necessary. Background Crawl space venting is generally viewed as good practice despite the obvious moisture problems that occur when outside air with a dew point higher than interior crawl space surface temperature is permitted to enter a crawl space. Unvented, conditioned crawl spaces with insulation on the perimeter solve this problem. Unvented, conditioned crawl spaces with insulation on the perimeter perform better in terms of safety and health (pest control), comfort (warm floors, uniform temperatures), durability (moisture) and energy consumption than passively vented crawl spaces with sub floor insulation. Perimeter insulation rather than floor insulation performs better in all climates from an energy conservation perspective. The crawl space temperatures, dew points and relative humidities track that of the house.
    [Show full text]
  • The Evolution of a Crawlspace – Lessons Learned from a Big Energy Retrofit
    The Evolution of a Crawlspace – Lessons Learned From a Big Energy Retrofit Presented by: Mike Barcik, Southface & Skye Dunning, BPS RESNET 2014 Conference 1 About Southface 2 Crawlspaces and the old way of thinking… • Moisture problems could be solved by venting • Hide stuff down there • Use vented crawlspace air for combustion • More vents are better, right? 1:150 rule of thumb • Hang batt insulation in cavities 3 Crawlspaces and the old way of thinking… • Moisture problems could be solved by venting • Hide stuff down there • Use vented crawlspace air for combustion • More vents are better, right? 1:150 rule of thumb • Hang batt insulation in cavities 4 Advantages of a Properly Retrofitted Closed Crawlspace • Forces you to address bulk moisture issues • Ensures you will have a Class I vapor retarder • Maintains interior crawlspace RH levels • Crawlspace is “nice” –greatly reduced mold risk • Floor above is more comfortable • Energy savings are generally the result • Requires you to fix or upgrade combustion equipment • Structure and hardwood flooring more stable • Reduces risk of pest damage (termites, bugs, vermin, etc.) • Ductwork is now inside conditioned envelope • Pipes inside conditioned crawlspace won’t freeze • Conditioned storage area in crawlspace 5 Disadvantages of a closed crawlspace • Costs $ to • upgrade combustion equipment • address all moisture issues • set up conditioning and maybe to operate • to remove old insulation and install new • add crawlspace monitoring/alert system • Radon levels could increase inside home • “Non‐believers” (e.g., some pest control people) don’t get it and can thwart the system • Cannot store chemicals, gas lawn equipment • Not necessarily appropriate to some crawlspaces (low clearance, flood plain, etc.) • Background of contractor influences outcome: • Water Proofing • Insulation • Pest Control 6 Code says to vent, but offers an exception… • 1:150 s.f.
    [Show full text]
  • The Closed Crawl Space: Making the Transition Climate Zones 3A & 4A
    TechSpecs A builder’s blueprint for construction technologies January 2013 The Closed Crawl Space: Making the Transition Climate Zones 3A & 4A G A What is a closed crawl space? E H A closed crawl space includes insulation on foundation walls, a ground F vapor retarder, and mechanical ventilation. B Some local jurisdictions allow insulation in the floor instead of the wall insulation. D Unlike a conventional crawl space, a closed A. Wood Floor Framing - p. 2 crawl space does not have wall vents and is C B. Foundation Wall - p. 2 air sealed to improve energy and moisture C. Moisture Management - p. 3 performance. A closed crawl space may also D. Ground Vapor Retarder - p. 3 be referred to as unvented, conditioned, E. Air Sealing - p. 4 semi-conditioned, or sealed. F. Wall Insulation - p. 5 G. Rim Insulation - p. 5 H. Mechanical Systems - p. 6 The modern closed crawl space is dry, Benefits of a Closed Crawl Space energy efficient, functional, and practical to build. This TechSpec presents an Dry and Durable Improved Whole-House Energy Efficiency Insulation, air sealing, moisture control Closed crawl space temperatures are more overview of benefits, code considerations, measures, and conditioned air provide a dry stable compared to an attic or a vented best practices, and solutions for closed under-floor space. crawl space. Locating ducts and mechanical crawl spaces. This information is intended equipment in a closed crawl space reduces to help home builders transition from a Marketable to Home Buyers heating and cooling loads. slab-on-grade or conventional vented Raised wood floor homes provide architectural appeal and a warm and Simplified Installation of Mechanical Systems crawl space, or to improve existing comfortable walking surface.
    [Show full text]