Overview:
There are so many things to consider when having a new home built - so many choices to make. How many bedrooms should you have? Is the kitchen large enough? Do you need a basement? You may even be concerned about environmental issues, such as the fumes from new building materials and furnishings. But are you concerned about radon? You should be..
Reprinted from the:
United States Environmental Protection Agency
Indoor Environments Division
Office of Radiation and Indoor Air
EPA 402F-98-001, September 1998
What You Should Know About
Radon
Radon is a radioactive gas that comes from the soil. Exposure to radon gas it the
second-leading cause of lung cancer (after smoking) in the United States. About 14,000
people die each year from radon-related lung cancer.
Radon is produced from the natural breakdown of the uranium found in most rocks and
soils. As it further breaks down, radon emits atomic particles. These particles are in the
air we breathe. Once inhaled, they can be deposited in our lungs. The energy associated
with these particles can alter cell DNA, thus increasing the risk of lung cancer.
Radon ususally does not present a health risk outdoors because it is diluted in the
open air. Radon can, however, build up to dangerous levels inside a house.
How Radon Enters a House
Radon can enter your new house through cracks or openings in the foundation. The
differences in air pressure between the inside of a building and the soil around it also
play an important role in radon entry. If the air pressure of a house is greater than the
soil beneath it, radon will remain outside. However, if the air pressure of a house is
lower than the surrounding soil (which is usually the case), the house will act as a
vacuum, sucking radon gas inside.
Because radon comes from the soil, the geology of an area can help to predict the
potential for elevated indoor radon levels. The U.S. Environmental Protection Agency (EPA)
has worked with state and federal geologists to develop maps
which predict the potential indoor radon levels for every county in the United States.
Those counties with the highest potential are designated as Zone 1; those with the lowest
comprise Zone 3.
Zone 1 areas have predicted average radon levels at or above the EPA's 4.0 pico-Curies
per liter (pCi/L) action level. (pCi.L is a measure of the amount of radioactivity in a
known quantity of air.) To determine which radon zone your new house will be built, please
contact your State radon office. If you are building in a Zone 1 county, you should
include a radon control system in your new home. It is an inexpensive addition to the
total cost of your house an is an easy way to protect you and your family.
Talk to Your Builder About
Radon Protection
You and your builder can design your new house to be radon resistant. For $350 to $500,
on average, your builder can take the following four simple steps to deter radon from
entering your home.
- Install a layer of clean gravel or aggregate beneath the slab or flooring system.
- Lay polyethylene sheeting on top of the gravel layer.
- Include a gas-tight venting pipe from the gravel level through the building to the roof.
- Seal and caulk the foundation thoroughly.
These construction techniques will be familiar to your builder. There is no need to
hire a special contractor or architect. Many builders already incorporate some of these
steps in the construction of their houses to control moisture or increase energy
efficiency. In fact, radon-resistant construction techniques can be found in the 1995
version of the One-and-Two Family Dwelling Code published by the Council of
American Building Officials.
Understanding a Radon System
The radon-resistant construction techniques described in this brochure comprise a
"passive" radon system. This system overcomes the vacuum effect experienced by
most houses by creating a pressure barrier to radon entry. The system also includes a pipe
to vent radon gas safely to the outdoors.
Sometimes a passive radon system isn't enough to prevent radon from entering a house.
In this case, a fan can be installed to pull the radon gas from the underlying soil into
the vent pipe where it can be exhausted outside the house. The addition of a fan and its
associated wiring creates and "active" radon system.
Testing: The Final Word
The only way to know if your new home has a radon problem is to test. The EPA
recommends that average annual indoor radon levels do not exceed 4 pCi/L. If your home is
built with a passive radon system, you should test it immediately after moving in to make
sure that radon levels are below the EPA guideline. Remember: If your radon level is 4
pCi/L or above, a fan can be installed easily to lower radon levels well below this
guideline.
Even if you must install a fan, adding a radon control system to a house under
construction is much less expensive than installing one after the house is built. The
average cost for a radon control system in an existing house is between $500 and $2,500.
Adding radon-resistant construction now will save you unnecessary expense and worry later.
For Architectural
Drawings and Technical InformationA growing number of municipalities located in areas known to have high radon potential
now require or recommend that passive radon systems be installed in all new houses.
Contact your State Radon Office to determine if you are
building your new home in such an area.
Many publications are available to you. Here are just a few suggestions:
Where To Find Free Information
Also Available
- The Council of American Building Officials One- and Two-Family Dwelling Code Appendix F
also details radon-resistant techniques. Call (708) 799-2300.
For More Information
To gain more information about building a radon-resistant house or testing an existing
home, please contact the Radon Office in your State.
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