United States EPA/402-K-01-002 Environmental April 2001 Protection Agency

Office of Air and Radiation

Building Radon Out A Step-by-Step Guide On How To Build Radon-Resistant Homes

Building Radon Out

Disclaimer Acknowledgements

The U.S. Environmental Protection Building Radon Out: A Step-By-Step Contributions from training sessions of Agency (EPA) strives to provide Guide on How to Build Radon-Resistant Dave Murane of Sanford Cohen and accurate, complete, and useful Homes was developed by the Indoor Associates are also acknowledged. information. However, neither EPA nor Environments Division in the Office of any person contributing to the Radiation and Indoor Air at the U.S. In addition, EPA would like to gratefully preparation of this document makes Environmental Protection Agency. The acknowledge the review and any warranty, express or implied, with lead EPA staff on the document was contributions of Terry Brennan, respect to the usefulness or Paulina Chen. Other staff contributing Camroden Associates; Robert Brown, effectiveness of any information, to the development of this document International Code Council; Thomas method, or process disclosed in this were: Greg Brunner, Brenda Doroski, Dickey, City of East Moline, Illinois; material. Nor does EPA assume any Gene Fisher, Matt Hiester, Wendy Ken Ford, National Association of Home liability for the use of, or for damages Kammer, Jennifer Keller, Mike Rogers, Builders; Douglas Kladder, Western arising from the use of, any and David Rowson. Regional Radon Training Center; and information, method, or process Brad Turk, Mountain West Technical disclosed in this document. Much of the description of building Associates. techniques in this document is based Mention of firms, trade names, or on training materials prepared by commercial products in this document Douglas Kladder of the Center for does not constitute endorsement or Environmental Research and recommendation for use. Technology, Inc., including the book Protecting Your Home from Radon by Kladder, Burkhart, and Jelinek.

1 Table of Contents

5 Building the Framework: Introduction 6 Does It Make Sense To Build Homes Radon-Resistant?

9 Digging Deeper: Questions and Answers 10 What Is Radon? 11 Is Radon a Significant Health Risk? 12 Is Radon a Problem In Homes? 13 Is There a Safe Level Of Radon? 14 How Does Radon Enter a House? 15 How Does Air Pressure Affect Radon Entry? 16 Does Foundation Type Affect Radon Entry? 17 What Can You Do To Reduce Radon New Homes? 18 What Are The Radon-Resistant Features? 20 Is There a Way To Test The Lot Before Building? 21 Would I Incur Liability By Installing The Features? 22 Should All New Homes Be Built Radon-Resistant? 23 EPA Map of Radon Zones 24 List of Zone 1 Counties

2 27 Nuts and Bolts: Installation Guide Planning 29 Answer The Question: To Intall Or Not To Install? 30 Determine What Type Of System To Install 32 Determine Vent Pipe Location And Size

34 Installation 35 Basement and Slab-On-Grade Construction: Sub-Slab Preparation 36 Gravel 38 Perforated Pipe 40 Soil Gas Collection Mat 42 Plastic Sheeting 43 Seal Off And Label Riser Stub 44 Lay Foundation 45 Crawlspace Construction 51 Seal Openings 55 Install Vent Pipe 58 Sealing Ducts and Air Handling Units 59 Install Electrical Junction Box 60 Post-Occupancy Testing 62 Activate the System 64 Sold: Working With Homebuyers 64 Get An Edge On The Market 66 Make a Name For Yourself 68 What To Tell Homebuyers

72 Appendix A: Architectural Drawings 76 Appendix B: Glossary 78 Appendix C: For More Information 80 Appendix D: State Radon Contacts

3 4 Building the Framework: Introduction

Should You Be Concerned About Radon?

Yes.

Radon is a colorless, odorless gas that can cause lung cancer. Your customers rely on you to construct a high quality, safe home. You can easily make a difference in how much radon gets into the homes you build. By using a handful of simple building practices and common materials, you can effectively lower the radon level in the homes that you build, and build most radon problems right out of the house.

5 Introduction Does it make sense to build homes radon-resistant?

Absolutely. There are a number of You can gain a marketing advantage reasons why you should consider installing radon-resistant features. Offering homes with radon-resistant Industry surveys continue to features can attract more potential demonstrate a rapidly growing market home buyers, which can translate into for more energy-efficient, closing more sales and greater profits. environmentally-friendly, comfortable, Consumers are becoming more aware and healthy homes. Radon-reduction that radon is a health risk, and techniques are consistent with state-of- building a home with radon-resistant the-art energy-efficient construction. features could give buyers one more The features can also decrease reason to purchase a home from you. moisture and other soil gases entering About one in every six homes is being the home, reducing molds, mildews, built radon-resistant in the United methane, pesticide gases, volatile States every year, averaging about organic compounds, and other indoor 200,000 homes annually, according to air quality problems. When using these annual surveys of home builder techniques, follow the Model Energy practices conducted by the National Code (or other applicable energy codes) Association of Home Builders (NAHB) for weatherization, which will result in Research Center over the past decade. energy savings and lower utility bills for In high radon areas, about one in every the homeowner. three homes is built with the features.

6 Building Radon Out

It is a good investment for a It is effective Upgrading is easy home buyer A basic radon reduction system, called After occupancy, all homes should be a passive sub-slab depressurization tested for radon, even those built with radon-resistant features. EPA It is cheaper to install a radon- system, effectively reduces radon levels recommends that homes with radon reduction system during construction by an average of about 50% and, in levels at or above 4 picocuries per liter than to go back and fix a radon problem most cases, to levels below EPA’s action of air (pCi/L) be fixed. Homes with a identified later. On average, installing level. An upgraded system, called an passive system can be upgraded to an radon-resistant features during active sub-slab depressurization active system with the simple construction costs about $350 - $500, system, includes an in-line fan to installation of a special in-line fan to or even less if you already use some of provide even further reductions. further reduce the radon level. the techniques for moisture control or Typically, the passive system includes a energy efficiency. (Many builders who It is simple to install junction box in the attic to make the use the techniques have reported future installation of the fan easy. This actual costs of $100 or less.) In upgrade is also used by some builders contrast, retrofitting an existing home All of the techniques and materials are to control moisture in basements and will typically cost between $800 and commonly used in construction. No crawlspaces. $2500. special skills or materials are required.

7 8 Digging Deeper: Questions and Answers

This chapter digs deeper into some of the more commonly asked questions concerning radon-resistant new construction.

9 Questions and Answers What Is Radon?

Radon is a radioactive gas. It comes Radon levels are commonly expressed from uranium and radium in soils, in picocuries per liter of air (pCi/L), which can be found everywhere in the where a picocurie is a measure of world. Uranium is present in rocks radioactivity. such as granite, shale, phosphate and pitchblende. Uranium breaks down to radium, which then decays into radon. The national average of indoor radon This gas can easily move up through levels in homes is about 1.3 pCi/L. the soil into the atmosphere. Natural Radon levels outdoors, where radon is deposits of uranium and radium, not diluted, average about 0.4 pCi/L. man-made sources, produce most of the radon present in the air. Radon in the soil can be drawn into a Radon is in the soil and air everywhere building and can accumulate to high in varying amounts. levels. Every building or home has the potential for elevated levels of radon. People cannot see, taste, feel, or smell All homes should be tested for radon, radon. There is no way to sense the even those built with radon-resistant presence of radon. features. EPA recommends taking action to reduce indoor radon levels when levels are 4 pCi/L or higher.

10 Building Radon Out Is Radon A Significant Health Risk?

When radon enters a home, it decays The evidence that radon causes lung Radon is classified as a into radioactive particles that have a cancer is extensive and based on: Class A carcinogen (known to static charge, which attracts them to human data taken from studies of cause cancer in humans). particles in the air. These particles can underground miners carried out over get trapped in your lungs when you more than 50 years in five countries, Some other Class A breathe. As the radioactive particles including the United States and break down further, they release bursts Canada; human data from studies in carcinogens are arsenic, of energy which can damage the DNA in homes in many different nations, asbestos, and benzene. lung tissue. In some cases, if the lung including the U.S. and Canada; and tissue does not repair the DNA biological and molecular studies. correctly, the damage can lead to lung cancer. Radon decay particles are breathed into the Not everyone exposed to elevated levels lungs of radon will develop lung cancer, but Energy released from your risk of getting radon-induced lung radon decay products cancer increases as your exposure to damages DNA radon increases (either because the radon levels are higher or you live in the home longer). Smokers who have high radon levels in their homes are at an especially high risk for getting radon-induced lung cancer.

11 Questions and Answers Is Radon A Health Problem In Homes?

The risk of developing lung cancer from Have You Heard Of radon has been clearly demonstrated in Stanley Watras? Radon is the second leading underground miners. Did you know cause of lung cancer in the that the average lifetime radon Stanley J. Watras was a construction United States. exposure for the general population is engineer at the Limerick nuclear power about the same as the levels of plant in Pottstown, Pennsylvania. One Radon causes about 20,000 exposure at which increased risk has day, on his way to work, he entered the lung cancer deaths per year. been demonstrated in underground plant and set off the radiation monitor miners? alarms which help protect workers by detecting exposure to radiation. Safety personnel checked him out, but could A study released by the National The following is a sample of not find the source of the radiation. Academy of Sciences on February 19, organizations which state that radon is Interestingly, because the plant was 1998 called “The Health Effects of a health threat in homes: under construction at the time, there Exposure to Indoor Radon” is the most was no nuclear fuel at the plant. They definitive accumulation of scientific 4 U.S. Surgeon General discovered the source of radiation data on indoor radon. The report 4 American Medical Association exposure when Watras’s home was concludes that radon causes 15,000 - 4 American Lung Association tested and was measured to have very 22,000 deaths per year, making it the 4 Centers for Disease Control high radon levels (2,700 pCi/L). After second leading cause of lung cancer in 4 National Cancer Institute installing a radon-reduction system, the U.S. and a serious public health 4 National Academy of Sciences radon levels in the home tested below concern. 4 Environmental Protection Agency 4 pCi/L.

12 Building Radon Out Is There A Safe Level Of Radon?

There is no known safe level of radon. As your exposure to radon is increased, so is your risk for developing lung cancer. Even radon levels below 4pCi/L pose some risk.

Homes have been found with radon levels above 20, 100, and in rare cases even 2000 pCi/L. High indoor radon levels have been found in every state.

EPA, the Surgeon General, the Centers for Disease Control, and many other health organizations recommend that action be taken to reduce indoor radon levels at or above 4.0 pCi/L, which is a reasonably achievable level of radon in homes using currently available cost- effective techniques.

Radon is a significant risk. More people die from lung cancer caused by radon each year than from many other highly publicized causes of death.

* data from the National Safety Council, 1999 13 Questions and Answers How Does Radon Enter A House?

Four main factors drive radon entry 3. There are pathways for the radon to Common Radon Entry Points into homes. All of these factors exist enter the basement, such as small in most homes throughout the country. holes, cracks, plumbing penetrations, or sumps. All homes have radon entry 1. Uranium is present in the soil pathways. nearly everywhere in the United States. 4. An air pressure difference between 2. The soil is permeable enough to the basement or crawlspace and the allow radon to migrate into the home surrounding soil draws radon into the through the slab, basement or home. crawlspace.

14 Building Radon Out How Does Air Pressure Affect Radon Entry?

The air pressure in a house is generally Mechanical systems, such as the be the dominant driving force. Air lower than in the surrounding air and furnaces or central air conditioners, handlers and leaky return ducts can soil, particularly in the basement and may also contribute to the difference in not only draw in radon, they can also foundation levels. This difference in air pressure. In areas with very short distribute it throughout a home. pressure causes a house to act like a mild winters, mechanical systems can vacuum, drawing air containing radon and other soil gases in through foundation cracks and other openings. Some of the replacement air comes from the underlying soil and can contain radon.

One reason why this pressure difference occurs is because exhaust fans remove air from inside the house. Warm air rises up When this air is exhausted, outside air Replacement air enters and out through the house by enters the house to replace it. Another leaks in the building infiltration in lower cause for a pressure difference is that envelope. Air is levels. Soil gases are warm air rises and will leak from also drawn out by also drawn into the mechanical openings in the upper portion of the home where the house ventilation (e.g. contacts the ground. house when temperatures are higher bathroom fans and indoors than outdoors. This condition, clothes dryers) and known as “stack effect,” causes combustion exhaust. unconditioned replacement air to enter the lower portion of the house.

15 Questions and Answers Does Foundation Type Affect Radon Entry?

Because radon can literally be sucked Basement Slab-On-Grade into a home, any home can potentially have a radon problem. All conventional Radon can enter Radon can enter a house construction types have been through floor-to-wall home regardless of found to have radon levels exceeding joints and control whether or not there is the action level of 4 pCi/L. joints and cracks in a basement. Slabs the slab. built on grade can have just as many openings to allow radon to enter as do basements.

Crawlspace Manufactured Homes

The vacuums that Unless these exist within a home buildings are set up are exerted on the on piers without any crawlspaces causing skirting placed radon and other around them, gases to enter the interior vacuums can home from the earthen area below. cause radon to enter these types of Even with crawlspace vents, a slight homes as well. vacuum is still exerted on the crawlspace. Measurements in homes with crawlspaces have shown elevated radon levels.

16 Building Radon Out What Can You Do To Reduce Radon In New Homes?

You can easily draw radon away and help prevent radon from entering the Can we keep radon out by sealing home by with the following basic steps. the cracks?

You may already be employing many of Reduce stack effect Sealing large cracks and openings is these techniques in the homes that you Sealing and caulking reduce stack effect, important to do when you build a build. All of the techniques have and thus reduce the negative pressure in home, both in the lower portion of the additional benefits associated with lower levels in the home. home to reduce radon entry points, and them and they are very easy to install. in the upper portion of the home to Install air distribution systems so that soil reduce stack effect. However, field Install a sub-slab (or sub-membrane) air is not “mined” research has shown that attempting to depressurization system Air-handling units and all ducts in seal all of the openings in a foundation The objective of these systems is to basements and, especially, in crawlspaces is both impractical and ineffective as a create a vacuum beneath the should be sealed to prevent air, and stand-alone technique. Radon can foundation which is greater in strength radon, from being drawn into the system. enter through very small cracks and than the vacuum applied to the soil by Seamless ducts are preferred for runs openings. These small cracks and the house itself. The soil gases that are through crawlspaces or beneath slabs. openings are too small to locate and collected beneath the home are piped Any seams or joints in ducts should be effectively seal. Even if all cracks could to a safe location to be vented directly sealed. be sealed during construction, which outside. would be costly, building settlement may cause new cracks to occur. Use mechanical barriers to soil gas entry Therefore, sealing large cracks and Plastic sheeting and foundation sealing openings is one of the key components and caulking can serve as barriers to of radon-resistant construction, but not radon entry, entry of other soil gases, the only technique that should be and moisture. employed.

17 Questions and Answers What Are The Radon-Resistant Features?

The techniques may vary for different What pulls the soil gas through foundations and site requirements, but the pipe? the basic elements of the passive sub- slab depressurization system are If the pipe is routed through warm shown on the opposite page. space (such as an interior wall or the furnace flue chase, following local fire In many parts of the country, the codes), the stack effect can create a gravel beneath the slab (gas-permeable natural draft in the pipe. Because this layer), plastic sheeting, and sealing and method requires no mechanical caulking are already employed for devices, it is called a passive soil moisture reduction. In these cases, depressurization system. simply adding the vent pipe and junction box is extremely cost-effective If further reduction is necessary to for reducing radon, and so cost- bring radon levels in a home below the effective that even a cost-conscious action level of 4 pCi/L or even lower, an builder like Habitat for Humanity has in-line fan can be installed in the pipe been adding these features in many of to activate the system. The system is its homes. then called an active soil depressurization system. The future There are more in-depth discussions installation of the fan can be made about installing the features in the next easier with a little planning during chapter. 18 Building Radon Out

A. Gas Permeable Layer Usually a 4-inch layer of clean, coarse gravel is used beneath the slab to allow the soil gas to move freely underneath the house. Other options are to install a loop of perforated pipe or soil gas collection mat (also known as drainage mat or soil gas matting).

B. Plastic Sheeting Polyethylene sheeting is placed on top of the gas permeable layer to help prevent the soil gas from entering the home. The sheeting also keeps concrete from clogging the gas permeable layer when the slab is poured.

C. Vent Pipe A 3- or 4-inch (recommended) PVC or other gas-tight pipe (commonly used for plumbing) runs from the gas permeable layer through the house and roof to D. Junction Box E. Sealing and Caulking safely vent radon and other soil gases An electrical junction box is wired in All openings in the concrete foundation above the house. Although some case an electric venting fan is needed floor are sealed to prevent soil gas from builders have used 3-inch pipe, field later to activate the system. entering the home. Also, sealing and results have indicated that passive caulking the rest of the building systems tend to function better with envelope reduces stack effect in the 4-inch pipe. home. 19 Questions and Answers Is There A Way To Test The Lot Before Building?

Soil testing for radon is not Why not wait to install the operating costs by planning to route recommended for determining whether features until after the home is the pipe through warm space to a house should be built radon- completed and a radon test is maximize passive operation of the resistant. Although soil testing can be performed? system. done, it cannot rule out the possibility that radon could be a problem in the It is much easier and far less costly to house you build on that lot. Even if prepare the sub-grade to improve soil The best way to determine the radon soil testing reveals low levels of radon gas flow before the slab is cast. Also, level in a home: test the home for gas in the soil, the amount of radon the pipe itself can be run more easily radon after occupancy. that may enter the finished house through the house before it is finished. cannot be accurately predicted because This significantly improves aesthetics one cannot predict the impact that the and can reduce subsequent system site preparation will have on introducing new radon pathways or the extent to which a vacuum will be produced by the house. Furthermore, the cost of a single soil test for radon ranges from $70 to $150, and at least 4 to 8 tests could be required to accurately characterize the radon in the soil at a single building site. Therefore, the cost to perform soil testing is very high when compared with installing the passive radon system in high radon potential areas (see page 22 on high radon potential areas).

20 Building Radon Out Would I Incur Liability By Installing The Features?

New homes built in the United States • Model Standards and Techniques for are not required to meet a specified Control of Radon in New Residential radon level. You are not required to Buildings, EPA, March 1994 test a home, nor to guarantee that a home will meet a specified radon level. • Appendix F: One and Two-Family By installing radon-resistant features, Dwelling Code, 1995 Edition, Council you are proactively offering your home of American Building Officials buyers features designed to reduce radon levels. Adopting radon-resistant • Appendix D: International One and building techniques should not Two-Family Dwelling Code, 1998 increase your liability risks in any Edition, International Code Council jurisdiction as long as due care is exercised in following the proper • Appendix F: International Residential construction techniques. Especially in Code, 2000 Edition, International high radon areas, radon-resistant Code Council features may actually help you market and sell the homes you build. • Standard Guide for Radon Control Options for the Design and Once you have decided to build radon- Construction of New Low Rise resistant, you will want to make sure to Residential Buildings, E 1465-92, install the features properly. If your American Society for Testing and building code includes provisions for Materials the radon features, follow your code requirements. Otherwise, follow the guidance provided in this document or in any of the following documents:

21 Questions and Answers Should All New Homes Be Built Radon-Resistant?

All homes could benefit from having a EPA recommends that all If you are building in a Zone 2 or 3 radon reduction system. However, it is homes built in Zone 1 (high area, the homes you build could still especially cost effective to install the radon potential) areas have have high radon levels, particularly if features in homes with the greatest radon reduction systems. there is a radon “hot spot” in your potential for high radon levels. county. According to an annual survey by the NAHB Research Center, about NAHB also recommends using the The potential for elevated radon levels 60,000 homes in Zone 2 and 3 are built passive system in homes in high radon is not uniform throughout the United with radon-resistant techniques each potential areas (Zone 1). Zone 1 States. EPA and the U.S. Geological year. You may want to consider counties are listed by state on pages 24 Survey have identified areas of the applying the techniques in these areas and 25. country with the greatest potential for too. Since the map was developed, high radon levels. The map shown on many States have acquired additional the next page is the result of indoor information on high radon areas. radon measurements, local geology, Contact your state radon office for more and population densities in a combined information. effort to rank radon potentials in all counties across the U.S. The map Consumers have asked for the radon- indicates three radon potential zones reduction features in many different defined by the likelihood of finding parts of the country and in all three radon measurements within certain radon zones. ranges when a short-term closed building radon test is performed.

22 Building Radon Out

23 Introduction List of Zone 1 Counties

ALABAMA Mesa ILLINOIS Tazewell Shelby Marion Lincoln Lenawee Renville Flathead Calhoun Moffat Adams Vermilion Steuben Marshall Marion St. Joseph Rice Gallatin Clay Montezuma Boone Warren St. Joseph McPherson Mercer Washtenaw Rock Garfield Cleburne Montrose Brown Whiteside Tippecanoe Meade Metcalfe Roseau Glacier Colbert Morgan Bureau Winnebago Tipton Mitchell Monroe MINNESOTA Scott Granite Coosa Otero Calhoun Woodford Union Nemaha Nelson Becker Sherburne Hill Franklin Ouray Carroll Vermillion Ness Pendleton Big Stone Sibley Jefferson Jackson Park Cass INDIANA Wabash Norton Pulaski Blue Earth Stearns Judith Basin Lauderdale Phillips Champaign Adams Warren Osborne Robertson Brown Steele Lake Lawrence Pitkin Coles Allen Washington Ottawa Russell Carver Stevens Lewis and Clark Limestone Prowers De Kalb Bartholomew Wayne Pawnee Scott Chippewa Swift Liberty Madison Pueblo De Witt Benton Wells Phillips Taylor Clay Todd Lincoln Morgan Rio Blanco Douglas Blackford White Pottawatomie Warren Cottonwood Traverse Madison Talladega San Miguel Edgar Boone Whitley Pratt Woodford Dakota Wabasha McCone Summit Ford Carroll Rawlins Dodge Wadena Meagher CALIFORNIA Teller Fulton Cass IOWA Republic MAINE Douglas Waseca Mineral Santa Barbara Washington Greene Clark All Counties Rice Androscoggin Faribault Washington Missoula Ventura Weld Grundy Clinton Riley Aroostook Fillmore Watonwan Park Yuma Hancock De Kalb KANSAS Rooks Cumberland Freeborn Wilkin Phillips COLORADO Henderson Decatur Atchison Rush Franklin Goodhue Winona Pondera Adams CONNECTICUT Henry Delaware Barton Russell Hancock Grant Wright Powder River Arapahoe Fairfield Iroquois Elkhart Brown Saline Kennebec Hennepin Yellow Medicine Powell Baca Middlesex Jersey Fayette Cheyenne Scott Lincoln Houston Prairie Bent New Haven Jo Daviess Fountain Clay Sheridan Oxford Hubbard MISSOURI Ravalli Boulder New London Kane Fulton Cloud Sherman Penobscot Jackson Andrew Richland Chaffee Kendall Grant Decatur Smith Piscataquis Kanabec Atchison Roosevelt Cheyenne GEORGIA Knox Hamilton Dickinson Stanton Somerset Kandiyohi Buchanan Rosebud Clear Creek Cobb La Salle Hancock Douglas Thomas York Kittson Cass Sanders Crowley De Kalb Lee Harrison Ellis Trego Lac Qui Parle Clay Sheridan Custer Fulton Livingston Hendricks Ellsworth Wallace MARYLAND Le Sueur Clinton Silver Bow Delta Gwinnett Logan Henry Finney Washington Baltimore Lincoln Holt Stillwater Denver Macon Howard Ford Wichita Calvert Lyon Iron Teton Dolores IDAHO Marshall Huntington Geary Wyandotte Carroll Mahnomen Jackson Toole Douglas Benewah Mason Jay Gove Frederick Marshall Nodaway Valley El Paso Blaine McDonough Jennings Graham KENTUCKY Harford Martin Platte Wibaux Elbert Boise McLean Johnson Grant Adair Howard McLeod Yellowstone Fremont Bonner Menard Kosciusko Gray Allen Montgomery Meeker MONTANA National Park Garfield Boundary Mercer Lagrange Greeley Barren Washington Mower Beaverhead Gilpin Butte Morgan Lawrence Hamilton Bourbon Murray Big Horn NEBRASKA Grand Camas Moultrie Madison Haskell Boyle MASSACHUSETTS Nicollet Blaine Adams Gunnison Clark Ogle Marion Hodgeman Bullitt Essex Nobles Broadwater Boone Huerfano Clearwater Peoria Marshall Jackson Casey Middlesex Norman Carbon Boyd Jackson Custer Piatt Miami Jewell Clark Worcester Olmsted Carter Burt Elmore Jefferson Pike Monroe Johnson Cumberland Otter Tail Cascade Butler Fremont Kiowa Gooding Putnam Montgomery Kearny Fayette MICHIGAN Pennington Chouteau Cass Kit Carson Idaho Rock Island Noble Kingman Franklin Branch Pipestone Custer Cedar Lake Kootenai Sangamon Orange Kiowa Green Calhoun Polk Daniels Clay Larimer Latah Schuyler Putnam Lane Harrison Cass Pope Dawson Colfax Las Animas Lemhi Scott Randolph Leavenworth Hart Hillsdale Ramsey Deer Lodge Cuming Lincoln Shoshone Stark Rush Lincoln Jefferson Jackson Red Lake Fallon Dakota Logan Valley Stephenson Scott Logan Jessamine Kalamazoo Redwood Fergus Dixon 24 Building Radon Out

Dodge Somerset Steuben Licking Indiana Edmunds Lewis Fairfax Jefferson Big Horn Douglas Sussex Sullivan Logan Juniata Faulk Lincoln Falls Church Marshall Campbell Fillmore Warren Tioga Madison Lackawanna Grant Loudon Fluvanna Mercer Carbon Franklin Tompkins Marion Lancaster Hamlin Marshall Frederick Mineral Converse Frontier NEW MEXICO Ulster Mercer Lebanon Hand Maury Fredericksburg Monongalia Crook Furnas Bernalillo Washington Miami Lehigh Hanson McMinn Giles Monroe Fremont Gage Colfax Wyoming Montgomery Luzerne Hughes Meigs Goochland Morgan Goshen Gosper Mora Yates Morrow Lycoming Hutchinson Monroe Harrisonburg Ohio Hot Springs Greeley Rio Arriba Muskingum Mifflin Hyde Moore Henry Okanogan Johnson Hamilton San Miguel N. CAROLINA Perry Monroe Jerauld Perry Highland Pend Oreille Laramie Harlan Santa Fe Alleghany Pickaway Montgomery Kingsbury Roane Lee Pendleton Lincoln Hayes Taos Buncombe Pike Montour Lake Rutherford Lexington Pocahontas Natrona Hitchcock Cherokee Preble Northampton Lincoln Smith Louisa Preston Niobrara Hurston NEVADA Henderson Richland Northumberland Lyman Sullivan Martinsville Skamania Park Jefferson Carson City Mitchell Ross Perry Marshall Trousdale Montgomery Spokane Sheridan Johnson Douglas Rockingham Seneca Schuylkill McCook Union Nottoway Stevens Sublette Kearney Eureka Transylvania Shelby Snyder McPherson Washington Orange Summers Sweetwater Knox Lander Watauga Stark Sullivan Miner Wayne Page Wetzel Teton Lancaster Lincoln Summit Susquehanna Minnehaha Williamson Patrick Uinta Madison Lyon N. DAKOTA Tuscarawas Tioga Moody Wilson Pittsylvania WISCONSIN Washakie Nance Mineral All Counties Union Union Perkins Powhatan Buffalo Nemaha Pershing Van Wert Venango Potter UTAH Pulaski Crawford Nuckolls White Pine OHIO Warren Westmoreland Roberts Carbon Radford Dane Otoe Adams Wayne Wyoming Sanborn Duchesne Roanoke Dodge Pawnee NEW YORK Allen Wyandot York Spink Grand Rockbridge Door Phelps Albany Ashland Stanley Piute Rockingham Fond du Lac Pierce Allegany Auglaize PENNSYLVANIA RHODE ISLAND Sully Sanpete Russell Grant Platte Broome Belmont Adams Kent Turner Sevier Salem Green Polk Cattaraugus Butler Allegheny Washington Union Uintah Scott Green Lake Red Willow Cayuga Carroll Armstrong Walworth Shenandoah Iowa Richardson Chautauqua Champaign Beaver S. CAROLINA Yankton VIRGINIA Smyth Jefferson Saline Chemung Clark Bedford Greenville Alleghany Spotsylvania Lafayette Sarpy Chenango Clinton Berks TENNESSEE Amelia Stafford Langlade Saunders Columbia Columbiana Blair S. DAKOTA Anderson Appomattox Staunton Marathon Seward Cortland Coshocton Bradford Aurora Bedford Augusta Tazewell Menominee Stanton Delaware Crawford Bucks Beadle Blount Bath Warren Pepin Thayer Dutchess Darke Butler Bon Homme Bradley Bland Washington Pierce Washington Erie Delaware Cameron Brookings Claiborne Botetourt Waynesboro Portage Wayne Genesee Fairfield Carbon Brown Davidson Bristol Winchester Richland Webster Greene Fayette Centre Brule Giles Brunswick Wythe Rock York Livingston Franklin Chester Buffalo Grainger Buckingham Shawano Madison Greene Clarion Campbell Greene Buena Vista WASHINGTON St. Croix NEW Onondaga Guernsey Clearfield Charles Mix Hamblen Campbell Berkeley Vernon HAMPSHIRE Ontario Hamilton Clinton Clark Hancock Chesterfield Brooke Walworth Carroll Orange Hancock Columbia Clay Hawkins Clarke Clark Washington Otsego Hardin_ Cumberland Codington Hickman Clifton Forge Ferry Waukesha NEW JERSEY Putnam Harrison Dauphin Corson Humphreys Covington Grant Waupaca Hunterdon Rensselaer Holmes Delaware Davison Jackson Craig Greenbrier Wood Mercer Schoharie Huron Franklin Day Jefferson Cumberland Hampshire Monmouth Schuyler Jefferson Fulton Deuel Knox Danville Hancock WYOMING Morris Seneca Knox Huntingdon Douglas Lawrence Dinwiddie Hardy Albany 25 26 Nuts and Bolts: Installation Guide

Installation is easy.

○○○○○○○○○○○○○○○○○○○○○ As you’ll see in this chapter, installing radon-resistant features is simple, because you use common building practices and materials.

Proper installation of the radon- resistant features is very important. Improper installation could actually increase indoor radon levels.

This section gives you step-by-step instructions - the nuts and bolts - on how to install radon-resistant features.

The techniques in this document apply primarily to new one- and two- family dwellings and other residential

○○○○○ buildings three stories or less in height.

27 Step-By-Step Installation Guide Planning Step 1 Planning Answer The Question: To Install Or Not To Install?

To help you answer this question, Do you want to reap the benefits Are you building in a Zone 1 area? consider the following points: ? of installing the features? ? Check the radon potential map and the The features not only protect your list of Zone 1 counties in the previous customer’s health, they also affect your chapter. Some states and counties bottom line: your profit. A small have done further research on radon investment up front on your part may potential, and you can check with your make a big difference in return down state or county government to find out the road, particularly as home buyers whether additional information is are increasingly looking for available. environmentally-conscious builders and healthy homes. If you are building in a Zone 1 area, you should install radon-resistant features in the homes that you build. Some builders also choose to install the features in Zone 2 and 3 areas, particularly if radon-resistant construction is a common practice in their area.

28 Building Radon Out

Are you required by code to use Are other builders in your area Are the home buyers in your area ??radon-resistant techniques? installing radon-resistant ? interested in features that features? improve indoor air quality or Some states and local juridisdictions energy efficiency? have adopted Appendix F of the 1995 If so, you may want to find out why they CABO One & Two Family Dwelling Code, are installing the features, how much it A sub-slab depressurization system not Appendix D of the 1998 International One costs to install the features in your only helps to reduce indoor radon levels, & Two Family Dwelling Code, or a area, and what the market response but also may help to reduce moisture similar code requiring installation of has been. and other soil gases. The techniques the radon-resistant features. The also improve energy-efficiency, which International Code Council’s new can translate into energy savings for International Residential Code, the home buyer. published in early 2000, also contains a voluntary appendix for radon-resistant construction requirements that becomes effective if the appendix is adopted with the code. If you don’t already know what is required in your area, check with your local code official for more information. 29 Step-By-Step Installation Guide

Planning Step 2 Passive System Determine What Type Of System To Install in Crawlspace

Recommended Option

There are three general types of radon- Passive sub-slab or sub-membrane reduction systems that builders have depressurization system installed. It is cost-effective and recommended to install a complete passive sub-slab or sub-membrane depressurization system, which would be fully- functioning as soon as construction is Passive System in Basement or with finished. The home should be tested Slab-on-grade after occupancy, and the passive system should be activated if post- occupancy testing reveals radon levels at or above 4 pCi/L.

30 Building Radon Out

Active System Upgraded Option Not Recommended in Basement or with Slab-on-grade Active sub-slab or sub-membrane Passive system “rough-in” depressurization system

Activating a passive system by adding Some builders perform only the sub-slab an in-line fan would be an effective preparation and stub the vent pipe upgrade during construction. Virtually above the slab. A vent pipe can be all homes with an active system have connected and routed through the home radon levels below the 4 pCi/L action and roof later if radon levels are high. level. This is not the recommended approach. It is much more cost- effective to run the vent pipe through the house during construction rather than after the walls have been closed up. However, if you elect to “rough in” a radon-reduction system, it is important to be clear with the home buyer that the home is not equipped with a functioning system. Be sure to seal off the riser stub so that radon is not being vented into the living space. Also, label the stub so it is not used as a plumbing waste line. 31 Step-By-Step Installation Guide

Planning Step 3 Determine Vent Pipe Location And Size

Route Pipe Through Warm Spaces

The vent pipe exhausts radon collected proper clearances consistent with local In hot climates and predominantly air- from beneath the slab or crawlspace. building and fire codes. This means conditioned houses, the passive stack One objective of a radon system in a that the riser should be brought up will depend more on wind, a hot attic, new home is to install it in such a through the slab within the same room and sun heating the pipe. manner that a natural draft occurs in as the furnace or water heater. This the pipe to draw the radon from the soil requires a little planning on your part without the use of a fan. To accomplish to identify this location before the slab this, route the pipe up through a warm is poured and to allow for sufficient part of the house and exhaust it room in the chase. through the roof. In cold climates, do not route the pipe Ideally, the vent pipe should be up through an outside wall. Routing the installed in a vertical run, with the pipe up an outside wall will reduce the least number of elbows which could natural thermal stack effect in the vent restrict air flow. A radon vent pipe can pipe, reducing its effectiveness. It will also be run through the same chase as also make it difficult to install a fan in the furnace and water heater flue. Do the attic if it is needed later on. A not tie them together, but rather allow better option is to route the pipe up for enough room to route the radon through an interior wall. vent pipe up alongside the flues with

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Discharge Location Use 4-inch Pipe When Possible

To prevent radon from re-entering the If you are routing the pipe through the When deciding between 3-inch and house or any other nearby buildings, same chase as the furnace flue, the 4-inch pipe (PVC or ABS), the 3-inch make sure the vent pipe exhausts: vent pipe needs to exit the roof at least pipe size is the minimum you should 10 feet away from the furnace flue. use. However, 4-inch pipe is the 4 a minimum of 12 inches above the Plan to elbow the pipe away from the preferred choice for a couple of reasons. surface of the roof flue in the attic to maintain this Field results have indicated that separation above the roof. However, passive systems tend to function better 4 a minimum of 10 feet away from any the additional elbows and horizontal with 4-inch pipe. A 4-inch pipe will also windows or other openings in the pipe length will restrict air flow through allow for a quieter system if the system building the pipe if the system is activated. Use is activated. 45 degree joints to reduce friction. 4 a minimum of 10 feet away from any windows or other openings in adjoining or adjacent buildings

33 Step-By-Step Installation Guide Installation

The type of system you install also depends on foundation type. Please see the pages listed below which correspond to the type of foundation you will be using.

Basement or Slab-on-Grade Crawlspace Combination Foundation

See page 35 See page 45 Treat each foundation separately and use the appropriate techniques for each foundation segment. Pay special attention to the points at which different foundation types join, because soil-gas entry routes exist in such locations. For an alternative, see page 43.

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Installation Step 1

Basement and Slab-on-Grade Construction: Sub-Slab Preparation

If the house you are building has a slab- Perforated Pipe Alternative Soil Gas Collection Mat on-grade or basement foundation, the Alternative radon gas must be able to move laterally beneath the slab to the location where In some regions of the country, gravel In some areas, the perforated pipe the vent pipe collects the gas. There is not a feasible option, either because option may not be feasible if the labor are three basic methods for improving native soils are sufficiently permeable needed to dig a trench for the pipe loop soil gas collection beneath slabs. and gravel is not required for water is too expensive, or if sub-grade soils drainage, or because lack of local supply are compacted or frozen. The third Gravel makes gravel very expensive. One option is to install interconnected strips alternative is to use the native fills of drainage mats (soil gas mats) on top beneath the slab and lay in a loop of of the sub-grade and beneath the slab. This option is generally chosen in perforated pipe to improve soil gas Drain mats consist of plastic material regions of the country where gravel is movement. This method is already that resembles an egg crate. Wrapped plentiful and economical or where employed in some homes with the use around the “egg crate” is a geotextile gravel is required by the building code of a drain tile loop. The loop of filter fabric that allows for the passage for water drainage. A continuous four- perforated pipe works well because the of air but prevents the infiltration of wet inch layer of ½-inch to ¾-inch clean (no soil gases need only move to the loop concrete. The mat can be laid directly fines) gravel placed beneath a slab rather than all the way across the slab on top of the prepared sub-grade, which provides a largely unrestricted path for as in the case of a single collection should be a uniform layer of sand radon to be collected. This size gravel point. (native or fill) a minimum of four provides a drainage layer and capillary inches thick. The concrete can be break for moisture control. poured directly over the soil gas collection mat.

For installation guidance, see page 36. For installation guidance, see page 38. For installation guidance, see page 40. 35 Step-By-Step Installation Guide

Installation Step 1A Gravel Option 1 Use post and beam construction by setting teleposts that support overhead beams on pads rather than continuous footings.

Option 2 Provide a means for air to flow through the grade beam. This is can be done by inserting at least two 4-inch pipe sleeves between the form boards or trench and pouring the grade beam over them. A minimum of two pipes should be installed at opposite ends of the grade beam. One pipe should be installed every 10 feet. Tape the ends Place a uniform layer of clean aggregate Grade Beam Obstructions so concrete does not enter the ends of under all concrete slabs or floor systems the pipe while pouring the footing. that directly contact the ground and are A grade beam or intermediate footing is Remove the tape when forms are within the walls of the living spaces. often installed beneath a slab to removed and before connecting to pipe Use a minimum 4-inch thick layer. support a load-bearing wall, presenting loop if a pipe loop is used. The gravel should be about ½- to ¾-inch a barrier to the lateral flow of air size. Smaller or fine gravel, or gravel beneath the slab to the soil gas Option 3 that is not as uniform in size, will collection point. There are a few Add a second riser on the other side of restrict air movement under the slab. options that can be used to avoid grade the grade beam. Tie the riser into the beam obstructions to soil gas air flow. vertical vent stack or run a second vent stack.

36 Building Radon Out

Recommended Improvement

Soil gas air flow can be somewhat restricted if the pipe is inserted into the gravel, and the gravel fills the pipe, especially if the system is later activated. To allow for airflow over a larger area, lay 3- or 4-inch perforated and corrugated pipe (recommended minimum Inserting Vent Pipe In Gravel length of 10 feet) in the gravel and connect it to the Place a 3- or 4-inch TEE fitting at the radon vent riser TEE fitting. location where you want the riser to Depending on the location of extend through the slab. The size of the riser, an elbow fitting the TEE or elbow will depend upon the may be used in place of a TEE diameter of vent pipe you will be fitting when using additional installing. piping in the gravel. Make sure that the concrete does Connect a short stub, at least 8 inches, not plug up the pipe during of 3- or 4-inch PVC pipe vertically into pour. the TEE.

37 Step-By-Step Installation Guide

Pipe Alternative Perforated Pipe

Lay a 3- or 4-inch diameter perforated What Kind Of Pipe Works How Much Pipe Do I Need? drain pipe in a trench around the Best? foundation perimeter just inside the Based on field work, it is recommended foundation footing. This could be the Perforated and corrugated pipe is to lay a continuous loop of 3- or 4-inch same pipe loop used for under-slab flexible, which makes it easy to lay diameter perforated pipe in the sub- drainage. Be sure the pipe is covered down in a trench. The perforations also grade with the top of the pipe located a by at least one inch of fill to keep allow for good soil gas collection. It is nominal one inch below the concrete concrete from filling perforations. recommended that the pipe be covered slab, for slab areas less than 2,000 with a geotextile cloth to prevent fines square feet. The pipe loop should be from clogging the holes. located approximately 12 inches from the inside of the exterior perimeter foundation walls. For slab areas greater than 2,000 square feet, but less than 4,000 square feet, the same configuration may be used but the pipe size should be a minimum of 4 inches in diameter. Slab designs in excess of 4,000 square feet should have separate loops for each 2,000 to 4,000 square feet depending upon the size of pipe utilized (3-inch or 4-inch).

38 Building Radon Out

Installation Tip

Install In Loops Rather Than Crossing Grade Beams Straight Sections In buildings where interior footings or The reason for laying out the pipe in a other barriers separate the sub-grade For a more secure connection, when loop is to allow for the soil gas to enter area, the loop of pipe should 3-inch corrugated pipe is used for the collection pipe from two sides. penetrate, or pass beneath, these the loop, the corrugated pipe can be Also, if the pipe is crushed at one point interior footings and barriers. Lay the inserted into a 4-inch PVC TEE by during the construction, the soil gas loop before the grade beams are securing with sheet metal screws. will still be drawn to the vent pipe. poured, or lay a length of non- When 4-inch corrugated pipe is perforated but corrugated pipe across used, 4-inch by 4-inch rubber the trench before pouring a grade couplings can be used to connect the Connecting Pipe Loop To Riser beam. If the latter method is used, perforated pipe to the solid PVC pipe tape off the ends of the pipe before stubs. Close the loop by connecting the ends pouring the beam, remove the tape to short pipe stubs and to opposite after pouring, and finish connecting the legs of a 3- or 4-inch PVC TEE. loop. Connect a short stub of 3- or 4-inch PVC pipe vertically into the TEE.

39 Step-By-Step Installation Guide

Mat Alternative Soil Gas Collection Mat

First, install a uniform layer of sand, a minimum of four inches thick. Next, place a layer of drainage matting over the sand, or lay a loop of matting inside the exterior perimeter foundation walls (no farther than a nominal 12 inches from the perimeter foundation walls). Mat material In buildings where interior footings or other barriers separate the sub-grade area, the matting should penetrate Use a soil gas collection mat or these interior footings or barriers to drainage mat having minimum form a continuous loop around the dimensions of one inch in height by 12 exterior perimeter. inches wide, and a nominal cross- Some mats that are sold for radon sectional air flow area of 12 square reduction are only ½-inch high and only Slabs larger than 2,000 sq. ft., but less inches. The mat matrix should allow have one side covered with a geotextile than 4,000 sq. ft., should have an for the movement of air through it and cloth. If this material is used, use a additional strip of matting that bisects yet be capable of supporting the weight minimum width of 24 inches. To keep the loop, forming two areas equally of the concrete above it. The matrix concrete from entering the matrix, it impacted by the two halves of the should be covered by a geotextile filter will need to be covered with geotextile rectilinear loop. Slab designs in excess cloth on all four sides to prevent dirt or cloth. Do not cover with plastic strips of 4,000 sq. ft. should have successive wet concrete from entering the matrix. because differential concrete drying loops of drain mat with one riser per Repair all breaches and joints in the can occur and cause a crack in the 4,000 sq. ft. of area. geotextile cloth prior to the pouring of concrete along the edge of the plastic. the slab. 40 Building Radon Out

Making Splices When making splices, slit the fabric of the two ends to be joined. Lay the Connecting Soil Gas Seal Cloth Tears With core from one end on top of the core from the other end with a three inch Collection Mat To Vent Pipe Duct Tape overlap. Lay the fabric back over the top of the splice and thoroughly seal with duct tape to keep the wet There is a special adaptor fitting that To insure that wet concrete does not concrete from seeping in. Drive at will accept the flat mat and adapt to a enter the mat interior, cuts and tears least two 8-inch long staples through round vent pipe (see graphic on right). should be sealed with duct tape. the mat at this point, being sure to This type of adaptor is available from drive them through the point where soil gas collection mat and drainage the two ends overlap. mat suppliers, and from radon Making TEEs in Mat mitigation equipment suppliers. The If you need to connect a length of mat is inserted into the flat ends and mat in the middle of another length the geotextile fabric is taped to the of mat, make a TEE by: cutting back edges to prevent wet concrete from the geotextile cloth, overlapping the entering the TEE. The top of the TEE is interior matrix, replacing the cloth, molded plastic to keep wet concrete out. securing with nails or landscape After the concrete is poured, the top can staples, and using duct tape to seal openings in the geotextile cloth. be cut with a hacksaw and a 4-inch riser inserted and glued or cemented Securing the Mat into place. Installation To keep the mat in place while the Tip concrete is being poured, the mat should be nailed down with 8-inch landscape staples, or 60 penny nails, about every seven feet.

41 Step-By-Step Installation Guide

Installation Step 1B Plastic Sheeting

Laying plastic sheeting between the gas Separate sections of sheeting should be permeable layer and the concrete slab overlapped by at least 12 inches. Below or floor assembly serves several a slab, it is not necessary to seal the important purposes. The sheeting can joint between overlapping sheets of prevent concrete from flowing down plastic. and clogging the gas permeable layer. It can also bridge any cracks that may develop in the slab or floor assembly, thereby reducing soil gas entry. Finally, the plastic sheeting can act as a vapor barrier to reduce moisture and Below: Thomas Dickey of the East other soil gas entry into the home. Moline, IL Health Department inspects plastic sheeting installed for a group of Prior to pouring the slab or placing the townhomes. floor assembly, lay a minimum 6-mil (or 3-mil cross laminated) polyethylene The sheeting should fit closely around or equivalent flexible sheeting material any pipe, wire or other penetrations. on top of the gas permeable layer. The sheeting should cover the entire floor area. Repair punctures or tears in the material. Duct tape may work for small, uniform tears or holes. For larger tears, cover with an additional piece of overlapping sheeting.

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Installation Step 1C Seal Off And Label Riser Stubs

Regardless of the sub- Alternative For Combination grade collection method used, you will have a Foundations short stub of pipe sticking up to which the Some builders have found it vent piping system will to be more economical to tie later be attached. Care the different foundations should be taken to together into a single riser. cover the end of the Place a pipe to connect the pipe so that it does not sub-grade area to the crawl become filled with space in the trench of the concrete when the slab intervening footing prior to is poured. pouring the foundation walls. This pipe should be 4-inch Label this stub so that perforated and corrugated someone does not pipe to prevent accumulation mistakenly think it is of water, which could block tied to the sewer and air flow. Cover with set a commode on it. geotextile cloth. Tape the ends of the cross-over to keep Support the stub, from getting debris in it until perhaps off a wall, so that the pipe can be connected to it stays vertical as the wet the slab and crawlspace concrete is poured. systems.

43 Step-By-Step Installation Guide

Installation Step 1D Lay Foundation

Foundation walls and slabs should be Dampproof foundation walls, and seal Similarly, some contractors will put a constructed to reduce potential radon any penetrations through the walls. layer of sand on top of the polyethylene, entry routes. In general, openings in both to protect it and to absorb water walls and slabs should be minimized, Slab from the concrete mix. This practice is and necessary openings and joints Pour a strong slab, and take steps to not recommended. The sand may should be sealed. control cracking. Although concrete become wet, from the concrete or rising slabs will almost inevitably crack, ground water, and would have to dry to Foundation Walls control joints can help the concrete to the interior through the concrete. The In poured concrete walls, all control crack in planned locations. As with the presence of the polyethylene sheeting joints, isolation joints, and any other foundation walls, all control joints or during this drying process may cause joints should be caulked with an other joints should be sealed with moisture problems above the slab. elastomeric sealant such as polyurethane caulk to reduce radon polyurethane caulk. entry. Trap any condensate or floor drains which pass through the slab, or route Hollow block masonry walls typically Do not deliberately puncture holes in them through non-perforated pipe to have cavities that can allow radon the plastic sheeting prior to pouring the daylight. Mechanical traps should be movement. To prevent this, hollow slab. Some contractors will do this to used rather than “wet” traps which can block walls should be topped with a allow excess water to drain from the wet dry out. continuous course of solid block or be concrete. Putting holes in the plastic grouted solid on the top. Alternatively, sheeting decreases (but does not Sump pits which are open to the soil or use a solid concrete beam at or above eliminate) its effectiveness as a soil- fed by drain tile loops should be the finished ground level or a full sill gas retarder. It is preferable to use covered with a gasketed lid. For more plate. concrete with a lower water-to-cement information on sumps, see page 52. ratio (low slump concrete).

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Installation Step 2 Crawlspace Construction

Crawlspaces are best treated by covering the entire crawlspace floor with plastic sheeting, laying a perforated collection pipe beneath the plastic sheeting, and connecting the pipe to the radon vent riser.

Crawlspaces should be constructed consistent with applicable building codes.

Access doors and other openings or penetrations between basements and adjoining crawlspaces should be closed, gasketed, or otherwise sealed with materials that prevent air leakage.

45 Step-By-Step Installation Guide

Crawlspaces Continued

Location Of Riser Install Plastic Sheeting Amount Of Plastic

The riser can be located anywhere in Clear the crawlspace area of objects Plan enough plastic to allow you to the crawlspace. It does not need to be which may puncture the plastic overlap seams by 12 inches. The in the center, so plan on placing it sheeting. edges should also be brought up on anywhere in the crawlspace that will be the foundation walls about 12 inches convenient for crawlspace access and Lay a continuous layer of minimum to allow for proper adhesion. It is for routing the pipe up through the 6-mil (or 3-mil cross-laminated) critical to allow for enough excess house. polyethylene sheeting or equivalent plastic so if a vacuum is drawn membrane material to cover the entire underneath the plastic, the plastic can Install Pipe crawlspace area. conform to the surface of the crawlspace floor (like vacuum Lay a length (usually five feet or more) packaging). If the amount of excess of 3- or 4-inch diameter corrugated and plastic is insufficient, the plastic may perforated pipe or a strip of geotextile stretch over a depression in the dirt drain matting on the soil at the location like a trampoline. where you will run the radon vent pipe up.

46 Building Radon Out

Optional Improvement Special Precautions Type Of Plastic It may be necessary to take special precautions to ensure that the plastic The minimum thickness of plastic is a 6-mil polyethylene sheeting. sheeting will not be damaged after However, this material is not very durable if the crawlspace will be accessed occupancy. In high traffic areas, the frequently or if occupants would like to use this area as storage. Regular 8- polyethylene should be overlain by to 10-mil sheeting would provide better puncture resistance. High-density, heavier material along expected traffic cross-laminated polyethylene has even greater puncture resistance and is routes. Various materials have been stronger and more durable. Unlike the regular polyethylene sheeting, which used for this purpose, including roofing can be torn by hand even with a thickness of 10 mil, the high-density cross- felt, EPDM rubberized roofing laminated material cannot be torn by hand, even though its thickness may membrane, and drainage mat. Also, if be only 4 mil. Due to its significantly increased puncture resistance, the there may be foot traffic over the entire cross-laminated polyethylene is recommended. The high-density sheeting crawlspace floor, or if the crawlspace is also available in white, making the crawlspace brighter and most suitable has very irregular floors, such as sharp for use as storage space. protruding rocks, it may be advisable to use thicker cross-laminated plastic sheeting or to lay a heavier material underneath the polyethylene, between the sheeting and the crawlspace floor.

47 Step-By-Step Installation Guide

Crawlspaces Continued Optional Improvement: Sealing seams and edges of plastic sheeting

Sealing The Sheeting Sealing Seams applying a continuous bead of sealant between the sheets in the 12-inch strip Although not required in current radon- Seams between adjoining sheets of where the sheets overlap. Firmly press resistant construction building codes, sheeting are usually sealed by the overlapping sheets together. increasing the air-tightness of the seams in the plastic sheeting may enhance the system’s effectiveness and integrity. Sealing should be sufficiently durable to withstand anticipated traffic through the crawlspace. To effectively seal the plastic sheeting, use a ½-inch wide bead of caulk.

Type Of Caulk

Polyurethane caulk will provide some adhesion to the polyethylene sheeting. However acoustical sealant, butyl rubber, or butyl acrlyic caulks form a more durable bond with the plastic. Field work suggests that other proprietary sealants are also effective, such as Proflex by GeoCel.

48 Building Radon Out

Sealing Edges And Seams For a more durable connection, trim the sheeting to pass beneath the consider using mechanical fasteners, obstruction and caulk the sheeting to Brush the walls with a wire brush at 6 such as strapping, to hold the plastic to the wall around the obstruction. At to 12 inches above the crawlspace floor the wall. If there is an obstruction to corners, cut and tuck plastic sheeting to remove any dirt or loose deposits. the wall within six to 12 inches of the neatly, and make sure that the sealing floor, such as a crawlspace access door, is also airtight. Make Plan on using one sure the 11-ounce tube of caulk sheeting to attach an 8-foot Keeping Plastic In Place lays flat length of plastic to on the While the caulk is curing, use duct tape along the seam to hold the sheets crawlspace the wall. together. The tape can secure the seam to keep the seam from breaking floor right during the cure as workers complete the installation. When sealing edges, up to the wall. Leave several inches of it is also a good idea to temporarily tape the free edge of the plastic so it will slack on the vertical section of the stay in place as the caulk cures. Place weights on the plastic to keep it from plastic rising up the wall to help prevent being pulled off the walls as you work on the balance of the crawlspace. the plastic from pulling on the seam due to foot traffic or by the system itself Vertical Pentrations when it is functioning. The sheeting needs to be sealed around posts and plumbing lines. It is easier to seal a large sheet to a flat apron section than to try to fit it Installation Secure plastic to the wall at 6 to 12 around the obstacle. You can use scraps of plastic to form an apron to fit Tip inches above the crawlspace floor with around these obstructions. Also, try to plan your seams along rows of a ½-inch wide bead of acoustical piers. When sealing around plumbing risers, make sure that the clean- sealant or butyl caulk along the wall. out is accessible.

49 Step-By-Step Installation Guide

Crawlspaces Continued

Riser Installation Label Riser And Plastic

The vent pipe needs to be connected It is a very good idea to label the riser to the perforated pipe beneath the within the crawlspace so it is not plastic in a manner that prevents air confused with any other plumbing. It leakage. The plastic sheeting can be is also a good idea to label the plastic wrapped around the vent pipe and to state that the plastic should not be taped to the pipe securely. removed and, if cut, it should be patched or replaced. Another way to prevent air leakage around the joint is to use two roof After home construction is completed, flashing hoods. One roof flashing goes inspect the sheeting for damage and below the plastic and one is placed repair as necessary. above the plastic to provide a flat area to which the plastic can be sealed. The riser is sealed by the rubber grommet on the roof flashing. The two roof flashings are then secured by sheet metal screws. Depending on the location of the riser, there may be either a PVC TEE or an elbow beneath the plastic that has a short 4-inch stub of pipe to which the corrugated and perforated pipe will be connected.

50 Building Radon Out

Installation Step 3 Seal Openings

After you pour the slab or place the floor Seal Floor-To-Wall-Joints Seal control joints assembly, seal major openings in the slab to retard soil gas entry through Floor-to-wall joints are critical places to Control joints in the concrete slab, openings in the slab or floor assembly. seal. Brush debris away from the joint whether they are saw cut or made with before applying caulk. Apply enough grooving tools, should be cleaned and Use materials that provide a caulk so when smoothed with a piece of filled with caulk. Even if they are not permanent airtight seal such as non- cardboard cut in a convex form, the cracked initially, they will likely shrink mortar, grouts, expanding foam, caulk will come out onto the floor and develop cracks in the future and or similar materials. When caulking up on the wall about 3/8-inch. The caulking them before the floor finishes slab openings, it is best to utilize a table on this page indicates the are in place makes sense. A gun-grade polyurethane caulk which has approximate length of joint that an polyurethane or a flowable polyurethane excellent adhesion characteristics for 11-ounce tube of caulk will cover. can be used. This seal does not concrete. The following are some interfere with the expansion of the examples of locations to be caulked control joint, but does block radon entry. after the concrete slab has cured and Joint Type Feet per before framing is installed. 11 oz. Tube

Cold 12

Expansion 8

51 Step-By-Step Installation Guide

Installation Step 3 Continued

Alternative: Tie Into Sumps maintenance is performed, consider using a sump cover with a transparent “door” or see-through The sump can also be incorporated viewing window. These doors, which into the radon system. are usually screwed into the cover Seal Open Sumps and sealed with a gasket, are If the sump is used without a drain generally large enough to permit tile loop, install a sump pit cover An open sump may allow radon into the limited access to the pump switch specifically designed to without removing the sump cover house from beneath the entire house accommodate a radon vent pipe and and breaking the seal. Windowed foundation. Make sure to cover and run the vent pipe directly from the sump covers are available for less seal the sump. The sump cover, which sump. These sump covers are than $50. available from numerous building must be removable to allow for regular supply stores, as well as catalog If the sump is connected to a drain maintenance and inspection of the firms dealing in equipment and tile loop, the radon vent pipe could be sump pump, is usually sealed by bolting supplies for radon migitation inserted directly into the sump or it directly to the slab or sump-liner lip contractors. into any convenient section of the and made airtight through the use of a drain tile loop (then cover and seal If the sump pit where the radon vent the open sump). Although installing gasket or silicone-caulk seal. pipe will be located also includes a the radon vent pipe in a remote pump, a cover can be ordered that section of the drain tile loop is If the sump is intended as a floor drain, includes both an opening for the slightly more difficult than directly radon vent pipe as well as holes for make sure the lid is equipped with a into the sump, it may offer a better the pump’s water discharge line and exhaust route through the home’s trapped drain to handle surface water electrical connection. Because interior spaces and may offer the on the slab. sump-cover removal and resealing is homeowner simplified access to the required every time pump sump.

52 Building Radon Out

Other Places To Seal The Slab And Foundation

Use a polyurethane caulk around Seal hollow block foundation walls at locations where plumbing and other the top. Use at least one continuous utility service lines pass through slab course of solid masonry, one course of and below-grade walls. masonry grouted solid, or a poured concrete beam at or above finished Use a full sill plate over the upper row of ground surface. Where a brick veneer block walls in basements or make the or other masonry ledge is installed, the upper row solid block. course immediately below that ledge should be sealed.

Caulk joints, cracks, or other openings around all penetrations of both exterior and interior surfaces of masonry block or wood foundation walls below the ground surface. Penetrations of poured concrete walls should also be sealed on the exterior surface. This includes sealing wall tie penetrations.

53 Step-By-Step Installation Guide

Installation Step 3 Continued

Other Considerations

Placing air handling ducts in or Placing air handling units in Avoid using floor drains and air beneath a concrete slab floor, or in crawlspaces, or in other areas below conditioning condensate drains which other areas below grade is not grade and exposed to soil gas, is not discharge directly into the soil below recommended unless the air handling recommended. However, if they are the slab or into the crawlspace. If system is designed to maintain installed in these areas, make sure installed, these drains should be continuous positive pressure within that they are designed or sealed in a routed through solid pipe to daylight or the ductwork. This is to prevent radon durable manner to prevent air through a trap approved for use in floor from being drawn into the ductwork and surrounding the unit from being drawn drains. Mechanical traps should be then distributed throughout the house. into the unit. used rather than “wet” traps which can dry out.

If ductwork does pass through a The bottom of channel-type (French) crawlspace or beneath a slab, it should drains should be sealed with a backer be of seamless material or sealed rod and caulking. Water drainage tightly. Where joints in the ductwork should be directed to a suitable drain. are unavoidable, seal to prevent air leakage.

54 Building Radon Out

Installation Step 4 Install Vent Pipe

Be sure to run the pipe up through the Do Not Trap Pipe roof before the roofer installs the roof Installation system. This will allow the roofer to Plan your pipe routing to minimize the Tip properly flash around the pipe. Avoid length of pipe and fittings and to angles in the pipe, if possible, to contain no traps. increase air flow through the vent pipe and maximize radon reduction. Do not install traps, intentional or Use either PVC or ABS pipe, accidental, in the pipe that will collect not both. The two types of Type Of Pipe water and restrict or stop air pipe require different movement. Air from the soil will have cleaners and cements. Use Schedule 40 PVC or ABS pipe. some moisture in it. As this air moves The pipe does not need to be pressure through sections of the vent pipe rated, so a pipe rated for Drain, Waste located in cold spaces, such as an attic, and Vent (DWV) applications will be the some moisture can condense. It is most cost effective. Do not use a pipe important that this water can drain thinner than Schedule 40. Do not use back down to the soil. Insulating the sheet-metal ductwork due to the pipe in the attic will reduce moisture likelihood of breakage or leaks at joints. condensation and maintain upward thermal draft in the pipe as it passes All joints should be primed and glued through unconditioned space. in a similar manner as indoor plumbing. Piping should also slope back to the suction pipe at a minimum angle of 1/8 inch per foot.

55 Step-By-Step Installation Guide

Installation Step 4 Continued

Allow For Future Installation Maintain Fire Resistive Rating Label Radon Vent Pipe Of Fan Of Walls And Ceilings Label the exposed portions of the pipe Although passive radon systems are If you route your vent pipe through the so other people will know that the pipe effective for reducing radon levels by wall between the house and the is not part of the sewer system during an average of about 50%, it is always a garage, you will need to put a fire- construction. It is recommended that good idea to plan ahead in case adding barrier around the pipe (on the inside the radon vent system be labeled in a an in-line fan is needed for further of the garage) to maintain the integrity conspicuous location on each floor radon reduction to bring indoor levels of the wall. Install a fire barrier with a level. Also, occupants and future below 4.0 pCi/L, or in case the future rating equal to the wall. occupants will know that it is part of a occupant wants to lower the radon “radon vent system.” levels as much as possible. During Note that some ceilings are also fire installation of the vent pipe, consider rated ceilings and will require fire Places to label include: these criteria for locating a future fan: barriers as well. 4 Fan cannot be inside the living space 4 Where riser exits slab of the house. 4 Where pipe is seen in closets 4 Fan cannot be in the crawlspace 4 Pipe run through attic beneath the home. 4 Fans are most often located in attics or garages (unless there is living space above the garage). 4 Fans require a 30-inch vertical run of pipe for installation. 4 Fans require an unswitched electrical junction box. 56 Building Radon Out

Installation Tip

Recommended Improvement: Screen On Discharge Support the pipe It is a good idea to put a 1/4-inch mesh Support the pipe using screen on the discharge to keep birds plumbers strapping at least from nesting in the pipe. once every 6 feet in horizontal runs and once Rain caps can reduce radon flow and every 8 feet in vertical runs. can force radon (if the system is activated) back down towards the Insulate the pipe openings into the living spaces. In In cold climates, insulate the most areas, they are not needed. For pipe where the pipe is routed very high rainfall areas, use alternative through unheated spaces, special devices which prevent large such as the attic. amounts of rain from entering the system while still allowing the air to vent up and away from the building. These devices are available through radon mitigation supply distributors. Another design option, which is more commonly used with commercial applications than with residential installations, is an annular rain cap as pictured here.

57 Step-By-Step Installation Guide

Installation Step 5 Seal Ducts and Air-Handling Units

HVAC systems should be carefully designed, installed and operated to avoid depressurization of basements and other areas in contact with the soil. Ideally, ductwork should remain in the conditioned space of the home. It is very important to seal joints in air ducts and plenums passing through unconditioned spaces such as attics, crawlspaces, or garages.

In addition to avoiding problems with unwanted air distribution, sealing ducts can save energy, make homes more comfortable, and lower heating and cooling costs.

58 Building Radon Out

Installation Step 6 Install Electrical Junction Box

For Future Installation of Fan

Although in most cases the passive For attics with interior access, many system alone is enough to keep radon building codes require a light in the levels below 4 pCi/L, occasionally the attic. In these cases, if the junction homeowner will want or need to box for the light is located at an activate the system by adding a fan to appropriate location for the fan, further lower radon levels in the home. another junction box will not be To prepare for this possibility, pre-wire necessary. If not, wiring the additional the attic when installing a passive outlet will be simple. The fan outlet system. An unswitched electrical does not require a dedicated circuit; it junction box should be installed in the may branch off the existing circuit for attic or garage within 6 feet of the vent the light. pipe. (See page 56 for a discussion about fan installation location.)

59 Step-By-Step Installation Guide

Installation Step 7 Post-Occupancy Testing

Testing is simple and easy. many kinds of low-cost "do-it-yourself" radon test kits you can get through the After the home is complete and mail and in hardware stores and other occupied, it should be tested to retail outlets. Coupons for short-term determine whether or not the passive and long-term radon test kits are also system needs to be activated. You available from the National Safety should recommend to the home buyer Council’s web site at that they test the home after they move www.nsc.org/EHC/indoor/coupon.htm. in and activate the system if the radon level is at or above 4 pCi/L. Types Of Radon Tests Some builders installing passive systems are testing the homes they Short-term Tests build and activating the passive radon systems if radon levels are at or above 4 The quickest way to test is with short- pCi/L. In all cases you should advise term tests. Short-term tests remain in the homeowners to retest sometime in the home for two days to 90 days, the future to confirm radon levels depending on the device. Because remain low. radon levels tend to vary from day to day and season to season, a short-term test is less likely than a long-term test to Obtaining a Test Kit give the home’s year-round average radon level. If you or the homeowner Note: The above figure illustrates one example of a radon testing device. There are many Radon test kits can often be obtained at need results quickly, a short-term test other types of radon testing devices available. your local hardware store. There are 60 Building Radon Out

followed by a second short-term test tests lasting just 2 or 3 days during Steps For Testing may be used, or two short-term tests unusually severe storms or periods of may be performed simultaneously. unusually high winds, because these If you are conducting the radon test conditions can affect the test results. prior to sale of the home, you will likely Long-term Tests want to get results as quickly as The test kit should be placed in the possible by following these testing Long-term tests remain in a home for lowest lived-in level of the home, for steps. If a homeowner is testing the more than 90 days. A long-term test example, the basement if it is to be home for radon, he or she should will give a reading that is more likely to frequently used, otherwise the first follow the longer steps on page 69. give a home’s year-round average radon floor. It should be put in a room that is level than a short-term test. used regularly, like a living room, Step 1 playroom, den or bedroom but not the Conduct a short-term test for at least kitchen or bathroom. Place the kit at 48 hours. After the first test has been How To Use a Test Kit least 20 inches above the floor in a completed, conduct a follow-up short- location where it won't be disturbed and term test for at least 48 hours. Follow the test kit instructions. For away from drafts, high heat, high short-term tests, close all windows and humidity, and exterior walls. Leave the Alternatively, take two short-term tests outside doors and keep them closed kit in place for as long as specified in at the same time in the same location throughout the test, except for normal the device instructions. Once the test for at least 48 hours. entry and exit. If you are doing a short- is completed, reseal the package and term test lasting just 2 or 3 days, be send it to the lab specified on the Step 2 sure to also close windows and outside package right away for analysis. You If the average of the two tests is doors at least 12 hours before beginning should receive test results within a few 4 pCi/L or more, activate the passive the test. Do not conduct short-term weeks. radon reduction system.

61 Step-By-Step Installation Guide

Optional Step 8 Activating the System

This section provides basic guidelines if its efficiency and life expectancy by you decide to install an in-line fan to minimizing exposure to extreme activate the system. Some states temperatures and moisture. require that in-line fans for radon Placement in a non-conditioned space reduction be installed by a prevents the accidental pumping of certified radon mitigation radon directly into a home should a contractor. Call your leak occur in the fan housing or at the state radon contact vent-pipe joints. for a list of certified contractors (see Building designs that call for a flat roof Appendix D for a list or cathedral ceiling, or some other of phone numbers). design feature that makes the attic installation unworkable, may Location necessitate placing the fan on the roof The fan and all positively pressurized or in an exterior venting pipe. portions of the vent pipe should be located outside habitable space in the Appropriate fan locations: building. 4 Unoccupied attic 4 Outside the house The ideal location is in the attic, or, 4 In garage perhaps, in an attached garage, where the fan housing and vent pipe can be Inappropriate fan locations: sheltered from the elements, yet be 7 In crawlspace outside the building’s conditioned 7 In basement spaces. Sheltering the fan maximizes 7 In occupied attic 62 Building Radon Out

Type Of Fan How To Install Install A System Failure Warning Device Although various types of fans are Install the fan in a vertical run of the suitable for this purpose, the most vent pipe. This will prevent outdoor A system failure warning device should commonly-used fans are centrifugal precipitation from accumulating in the be used to alert occupants to any fans often referred to as “in-line,” fan or fan housing. Do not use an malfunction of the system or drop in its “tubular” or “tube” fans. angled portion of the pipe. suction flows. Types of warning devices include pressure gauges, manometers The size and air movement capacity of To reduce vibrations and noise and visual or audible alarms. Unless the vent pipe fan should be sufficient transmission, use flexible air-tight the indicator is integral to the fan to maintain a pressure field beneath couplings instead of rigid couplings. power supply, the audible or visual the slab or crawlspace membrane that Secure couplings tightly to the fan alarm should be connected to a is lower than the ambient pressure using circular hose clamps. separate circuit so that it will activate above the slab or membrane. Most if power to the fan is interrupted. contractors have found 90-watt in-line In regions with prolonged or extreme fans to be adequate for most home cold, both fans and attic vent pipes styles, locations and sizes. You can should be insulated to reduce also look for a fan capable of moving condensation and the possibility of 100 cubic feet of air per minute at vent exhaust “freeze up.” Freeze-up is one inch of water column, which should most often found in regions with be sufficient for most applications. extremely cold winters and in systems having high air-flow rates as well as high moisture levels in the sub-slab soil.

63 Working With Homebuyers Sold: Working With Homebuyers

Get An Include A Brochure On Make The Radon System Edge On Radon Systems In All A Custom Feature The Market Sales Information

All homebuyers want to know that they Prominently list the availability of a Provide a pamphlet on the basics of a are buying a quality home. There are a radon system as a custom feature in all radon system in all hand-out sales few simple things that you can do to your sales, promotional, and materials. You might include radon educate your homebuyers that radon- advertising materials. Emphasize the maps from your specific geographical resistant features make sense both desirability of a radon system in the area, as well as easy-to-understand from a health and from an investment same way you would hardwood floors, information on why a radon system is standpoint. nine-foot ceilings, upgraded important, how it operates, the costs appliances, master bedroom suites, involved, and other questions that The activities suggested here are etc. These are all features that home buyers might ask when inexpensive and easy to implement. enhance the value of the house and considering a radon system. A number Doing them will make your company make it more enjoyable to live in. of useful consumer-oriented stand apart from the other builders in Stress the economic advantage of publications are available to be your area by demonstrating your adding a radon system while the home ordered in bulk, such as the brochure commitment to customer satisfaction is being built, thereby avoiding a more “Buying a New Home? How to Protect and healthy homes. expensive, retrofit installation. Your Family From Radon” and radon maps. See Appendix C for more information.

64 Building Radon Out

Use Your Model Home As Generate Buyer Educate Your Sales Team A Promotional Tool Awareness

All sales associates should be as Install a radon system in your model To increase home buyers’ awareness of knowledgeable and positive about the home. Advertise it as another, must- radon, consider the following value of a radon system as they are have feature that is desired by many promotional activities. about every other feature you offer. new home buyers. Consumers expect a Have them stress not only the builder to include the “latest and Print Media amenities you provide, but also the greatest” product offerings in the Prepare a news release on the solid construction techniques you model home; make a radon system one availability of your new homes. This offer, including a radon system. Help of those special elements and promote can include a complete discussion of your sales staff understand the radon it accordingly. features, size, location, floor plans, etc. system and how it works, so that they Prominently mention that you are the can explain its benefits to sales “only builder in your area” to offer prospects. An on-site review of the Post Signs radon systems (if this is appropriate and system by a construction supervisor is accurate). Explain why you have an excellent way to start. In addition, chosen to provide this important have your sales personnel become feature to members of your community. familiar with your radon information Highlight the value of a radon system by materials and ask them to go over placing an explanatory sign in the Website Promotion these materials with prospective home basement or near the crawlspace area More and more consumers are relying buyers. of your model home. This will make on the internet for information about prospective home buyers aware of the buying a new home. Develop a special system’s availability, function, and web page on radon systems to benefits. As you prepare to install integrate with your existing website. radon systems in your new homes, increase the interest of “drive-by” prospects by placing a “Radon System Being Installed” placard on the site.

65 Working With Homebuyers Make A Name For Yourself

One of the most effective ways of marketing radon systems is to Inform Newspaper Alert Local Realtors establish yourself as a knowledgeable Readers builder concerned about radon and equipped to do something about it. By providing consumers with general A well-conceived “letter to the editor” on Many realtors are familiar with the information about radon and radon the importance of safe indoor radon issue as it relates to existing systems, you will establish yourself as environments, and the contribution homes. Consider holding a seminar or a socially-responsible builder who is that radon systems can make, may informal gathering of local realtors to attentive to the health and well-being spark increased demand for radon discuss the importance of including of community families. This reputation systems and highlight their availability radon systems in new construction. Let is likely to give you an edge over your in your homes. them know that you are a builder who competitors by making your homes offers such systems in your houses and more desirable to today’s that you are willing to work with any health-conscious consumers. client they may have that is concerned about the possibility of radon in their The following marketing activities are home. simple ways to build your reputation in the community as a knowledgeable builder of quality, radon-resistant homes.

66 Building Radon Out

Consider A Public Service Offer Community Be A Television Star Announcement Education Materials

A radio public service announcement Brief, informational brochures or fact Community television programs on about radon’s health effects and the sheets on radon and radon systems “moving up” or “buying your dream value of a radon system in protecting can be developed for free distribution home” are always of interest to people is a relatively inexpensive, but in grocery stores, schools, libraries, consumers. Use these programs to highly effective, means of increasing banks, community centers, etc. These promote radon systems. Arrange to community awareness about radon materials can help increase awareness appear on a community-based and expanding the demand for radon of radon’s impact on the community television program and use the systems. Your 30-second and the value of radon systems in opportunity to talk about why you offer announcement can conclude by reducing radon exposure. Display radon systems in your homes. Local identifying your company as the your company’s name and logo on all cable stations are especially good sponsor of the information and a educational materials you distribute. outlets for this type of activity. builder who is interested in protecting people from radon.

67 Working With Homebuyers What To Tell Homebuyers

Once you have sold the house, there What Features Have Been conduct a radon test after they have are a few key items to tell your Installed? occupied the home. Let the homebuyer homebuyer about the radon features know where the system failure warning that you have installed in their new Let your home buyer know whether device is located and inform the home. you have installed a passive radon homebuyer that if the device indicates system, an active radon system, or a a system failure, the fan is no longer rough-in for a sub-slab depressurization working to vent radon out of the home. system. Explain what the features are The homeowner should then contact a designed to do. radon mitigation contractor to check the system. Passive System If you have installed a passive system, Rough-In For Sub-Slab Depressurization let the homebuyer know that they If you have installed a rough-in for sub- should test their home for radon. Tell slab depressurization, it is very the homeowner that if the tests important for the homebuyer to be indicate a radon level at or above the aware that the house has not been action level of 4 pCi/L, it is equipped with a functioning radon recommended that they hire a radon system. Explain that the home would mitigation contractor to activate the need to be tested for radon. If the tests system, or you could offer to activate indicate a radon level at or above the the system. action level of 4 pCi/L, it is highly recommended that the homebuyer hire Active System a radon mitigation contractor to install If you have installed an active system, the rest of the radon system. recommend to the homebuyer that they 68 Building Radon Out

Does This Mean This House How Does The Homebuyer Test Has High Radon? For Radon?

Some homebuyers may be concerned The following are recommended steps Step 3 that you have installed the radon for the homebuyer to test for radon If you followed up with a long-term system because the house has high once they have moved into the home. test: activate the passive system if the radon levels. Simply explain that there These steps are slightly different from long-term test result is 4 pCi/L or is no way of knowing whether or not a the steps outlined for builders on page higher. If you followed up with a home has high radon until the home is 61, because the homeowner has more second short-term test: consider completed and a radon test is time to perform long-term tests. activating the system if the average of performed. Tell them that a passive the two short-term tests is 4 pCi/L or system will reduce radon levels on Step 1 higher. The higher the short-term average by about 50%. Also tell them Conduct a short-term test for at least results, the more certain you can be that the home should be tested, and 48 hours. If the result is 4 pCi/L or that you should activate a passive that the system should be activated if higher, take a follow-up test (Step 2) to radon system. Once a system has been further reductions are desired or if be sure. activated, the radon testing should be radon levels are at or above 4 pCi/L. If repeated with a short-term test the radon features had not been Step 2 (preferably between 24 hours and 30 installed, it could cost $800 - $2500 to Follow up with either a long-term test or days after activation). fix a radon problem after construction a second short-term test. For a better has been completed. understanding of the year-round average radon level, take a long-term test. For faster results, take a second short-term test.

69 Working With Homebuyers

70 Building Radon Out

Hopefully, you now see the benefit of building homes with radon-resistant features, and you are familiar with the techniques for installing the features.

The following pages contain additional information which you may find useful, including architectural drawings, and information about how to order a video by the National Home Builders Association to view the features being installed.

Become one of the many builders nationwide who are helping to reduce the risks of radon!

71 Appendix

Appendix A Architectural Drawings

On the following pages are three architectural drawings of the passive, active, and crawlspace radon reduction systems to help you visualize the complete radon features as they should be installed.

These drawing are available in a larger format as EPA document 402-F-95-012, free through the National Service Center for Environmental Publications. They are also available electronically on the EPA website in .PDF files and as CAD drawings. For more information, see Appendix C.

72 Building Radon Out

Architectural Drawing Passive Sub-Slab Depressurization System Used for basement and slab-on-grade construction

73 Appendix

Architectural Drawing Passive Sub-Membrane Depressurization System Used for crawlspace construction

74 Building Radon Out

Architectural Drawing Active Sub-Slab Depressurization System Uses fan to mechanically draw air from beneath the slab (or membrane) through the vent pipe.

75 Appendix

Appendix B Glossary

Active System Condensation Footing Passive system with the addition of a Vapor in the air turns into water on The supporting base for the foundation fan to more actively draw radon from cold surfaces. Beads or drops of water walls of a house. the soil into the stack where it (and frost in extremely cold weather) dissipates into the atmosphere. A accumulate on the inside of the Gas-permeable system-failure warning device (alarm) exterior covering of a building when A material through which gas passes is also installed to alert the occupant if warm, moisture-laden air from the easily. the system is not working. interior reaches a point where the temperature no longer permits the air International Codes Action level to sustain the moisture it holds. Model codes published by the Home owners should take action to International Code Council (ICC) to lower radon levels indoors when levels Condensate drains combine all four model building codes are at or above 4 pCi/L. Drains which remove condensation into one. The International Residential from air-conditioning or other Code was published in early 2000. Aggregate equipment, frequently empty into the A coarse material, such as gravel, sump or below the slab. Junction Box placed below the slab. An enclosed box used to connect or Dampproofing branch electrical wiring. ASTM Standard Guide 1465-92 Sealing the foundation walls to prevent A guidance booklet published in 1992 outside moisture from entering the Map of Radon Zones by the American Society for Testing basement, although not as tightly as in EPA’s Map of Radon Zones assigns and Materials according to their water-proofing. each of the 3141 counties in the consensus process for deciding on the United States to one of three zones content. Drain Tile Loop based on radon potential: Typically refers to a length of Building Code perforated pipe extending around all or Zone 1 Criteria or requirements (i.e., minimum part of the footing perimeter for Counties have a predicted average standards) set forth and enforced by a draining water away from the indoor screening level greater than state or local agency for the protection foundation of a home. 4 pCi/L of public health and safety. Is usually based on a model code (see below) Flashing Zone 2 and/or Model Standards published by Material for reinforcing and Counties have a predicted average acknowledged organizations or weatherproofing the joints and angles indoor screening level between associations. of the roof and penetrations through 2 and 4 pCi/L the roof. 76 Building Radon Out

Zone 3 installation of a PVC pipe running from Stack Effect Reduction Techniques Counties have a predicted average beneath the slab to the roof. Works by Features that prevent or reduce the indoor screening level less than using natural pressure differentials flow of warm conditioned air upward and 2 pCi/L between the air in the pipe, and the out of the building superstructure. If rest of the home and the outside air. not reduced, stack effect can actually Elevated radon have been found in all draw soil gas containing radon into the counties (Zone 1, Zone 2 and Zone 3). Picocuries per liter (pCi/L) lower levels of the house. Most of A unit of measuring radon levels. these techniques are part of the Model Codes International Code Council’s Model Documents specifying requirements for Polyethylene Sheeting Energy Code. building, mechanical, plumbing, and (used as soil-gas-retarder) fire prevention installations. Often the Plastic sheeting, about drop cloth Sub-Membrane Depressurization basis for state and local building weight, used over gravel and under the A system designed to achieve lower codes. concrete slab to prevent soil gases from sub-membrane air pressure relative to entering a home. The sheeting also crawlspace air pressure by use of a vent Model Standard prevents the concrete from flowing into drawing air from beneath the soil-gas A document that has been developed the gravel and blocking air flow beneath retarder membrane. May be a passive and established to connote specified the slab. Also used as a moisture system (without fan) or active system consensus and approval of certain barrier. (with fan). techniques and standards. A prescribed level of acceptability or an approved PVC Pipe Sub-Slab Depressurization model used as a basis for comparison. A hollow plastic pipe generally used for A system designed to achieve lower Voluntary technical guidance until plumbing in home construction. sub-slab air pressure relative to indoor adopted into a building code. EPA has air pressure. May be a passive system published one for radon-resistant new Slab (no fan) or active system (with fan). construction, called Model Standards The concrete “floor” poured over the and Techniques for Control of Radon in ground between the foundation walls, Sump / Sump pit New Residential Buildings. either at ground floor or basement A hole going below the slab into which level. water is drained in order to be pumped Passive System out. Should be sealed to prevent Short for passive sub-slab Soil Gas radon from entering the home. depressurization system. Features to Any gas emanating from the soil, reduce radon levels by utilizing barriers including radon, methane, and water to radon entry and stack effect vapor. reduction techniques and the 77 Appendix

Appendix C For More Information

Hotlines EPA Website One and Two Family Dwelling Code. To National Safety Council Check out the Indoor Environments download the zipped PDF file visit the 1-800-55-RADON Division Home Page for information and International Code Council website at Answers consumers’ specific questions online publications about radon and www.intlcode.org/download/index.htm. dealing with radon indoor air quality: www.epa.gov/iaq ASTM E1465-92 Standard Guide for Consumer Federation of America Publications Radon Control Options for the Design and Foundation’s Radon Fix-It Program Protecting Your Home from Radon Construction of New Low Rise Residential 1-800-644-6999 Second edition, 1997 (Kladder, D.L., Buildings Answers questions for consumers with Burkhart, J.F., Jelinek, S.R.). This This guide covers design and high radon levels about how to fix the document details many radon-resistant construction methods for reducing problem construction techniques, and includes radon entry into new low-rise many useful photos and illustrations. It residential buildings and is intended to IAQ Info is available in many public libraries or assist designers, builders, building 1-800-438-4318 from the National Environmental officials and others involved in the Answers specific indoor air quality Health Association at construction of low-rise residential questions 1-800-513-8332 or www.neha.org. buildings. Available from the Literature referrals American Society for Testing and Radon-Resistant Construction and Materials. 100 Barr Harbor Drive, West National Hispanic Indoor Air Quality Hotline Building Codes Conshohocken, PA 19428-2959. 1-610- 1-800-SALUD-12 This document provides general 832-9585 or www.astm.org Bilingual health information specialists information on radon, and an provide answers about radon and explanation on each section in provide test kits to consumers with Appendix D of the 1998 International bilingual instructions 78 Building Radon Out

EPA Publications Model Standards and Techniques for Other Sources of Informaton Order copies in singles or in bulk from Control of Radon in New Residential the National Service Center for Buildings International Code Council (ICC) Environmental Publications (NSCEP) EPA/402-R-94-009 5203 Leesburg Pike, Suite 708 1-800-490-9198 or Falls Church, VA 22041 www.epa.gov/ncepihome/index.html EPA Map of Radon Zones (color) (703) 931-4533 EPA/402-F-93-013 (703) 379-1546 fax Sample of available publications: www.intlcode.org Radon Doesn’t Have to be a Problem ICC publishes model codes, including Building A New Home: Have You EPA/402-V-95-015 the International Residential Code (IRC). Considered Radon? 12-minute video by the National The IRC contains an Appendix on EPA/402-F-98-001 Association of Home Builders (NAHB) radon-resistant construction. They also Colorful brochure on the basics of explaining radon-resistant features. publish a separate guide to radon- radon-resistant features. resistant construction. Radon Resistant New Homes: A Public Buying A New Home? How To Protect Official’s Guide to Reducing Radon Risk Your Family From Radon EPA/402-V-95-014 EPA/402-F-98-008 Short video by the National Conference This brochure provides a quick of States on Building Codes and summary and diagram of the major Standards (NCSBCS) on radon-resistant components of the radon reduction features. system. Great for educating homebuyers about radon.

79 Appendix

Appendix D State Radon Contacts

For a complete, up-to-date listing, check the web page: www.epa.gov/iaq/radon/contacts.html.

Alabama (800) 582-1866 New Hampshire (800) 852-3345 x4674 Alaska (800) 478-8324 New Jersey (800) 648-0394 Arizona (602) 255-4845 x244 New Mexico (505) 476-8531 Arkansas (800) 482-5400 New York (800) 458-1158 California (800) 745-7236 North Carolina (919) 571-4141 Colorado (800) 846-3986 North Dakota (800) 252-6325 Connecticut (860) 509-7367 Ohio (800) 523-4439 Delaware (800) 464-4357 Oklahoma (405) 702-5100 District of Columbia (202) 535-2999 Oregon (503) 731-4014 x664 Florida (800) 543-8279 Pennsylvania (800) 237-2366 Georgia (800) 745-0037 Puerto Rico (787) 274-7815 Guam (671) 475-1611 Rhode Island (401) 222-2438 Hawaii (808) 586-4700 South Carolina (800) 768-0362 Idaho (800) 445-8647 South Dakota (800) 438-3367 Illinois (800) 325-1245 Tennessee (800) 232-1139 Indiana (800) 272-9723 Texas (800) 572-5548 Iowa (800) 383-5992 Utah (800) 458-0145 Kansas (800) 693-5343 Vermont (800) 439-8550 Kentucky (502) 564-4856 Virgin Islands (212) 637-4013 Louisiana (800) 256-2494 Virginia (800) 468-0138 Maine (800) 232-0842 Washington (360) 236-3253 Maryland (800) 438-2472 x2086 West Virginia (800) 922-1255 Massachusetts (800) RADON95 Wisconsin (888) 569-7236 Michigan (800) 723-6642 Wyoming (800) 458-5847 Minnesota (800) 798-9050 Mississippi (800) 626-7739 Tribal Radon Program Offices Missouri (800) 669-7236 Hopi Tribe (Arizona) (520) 734-2442 x635 Montana (800) 546-0483 Inter-Tribal Council of Arizona (602) 307-1527 Nebraska (800) 334-9491 Navajo Nation (520) 871-7863 Nevada (775) 687-5394 x275 Duckwater Shoshone-Paiute Tribe (702) 863-0222 (Nevada)

80 Building Radon Out

Note

As of 9/30/98, EPA no longer runs a National Radon Proficiency Program. Some states “regulate” providers of radon measurement and mitigation service providers and measurement devices by requiring registration, certification, or licensing. Some of these states issue identification cards. Call your state to learn more. You can also contact the National Environmental Health Association’s (NEHA) National Radon Proficiency Program at 1-800-269-4174 ([email protected]) or, the National Radon Safety Board (NRSB) at (303) 423- 2674 ([email protected]) for more information on radon proficiency.

81 BuildingRadon Out

This toolkit is designed to:

4 Answer your questions about radon and radon-resistant features in new homes

4 Give you step-by-step guidelines and tips on how to install radon-resistant features

4 Provide practical ideas on educating potential home buyers about the features