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Building
A New Home?
Have You Considered Radon?
There are many
things to consider when having a new home built - so many choices
to make.
You may even be
concerned about environmental issues, such as fumes from new
building materials and furnishings. But are you concerned about
radon? You should be!
Radon
Entry
Radon can enter
your new home 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 in
which radon zone your new house will be built, contact your State
radon office. (State
Radon Contacts) 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 and is easy
to protect you and your family.
Talk
To Your Builder
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 layer through the
building roof.
- Seal and chalk
the foundation thoroughly.
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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 into 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 comprise a "passive"
radon system. This system overcomes the vacuum effect experienced
by most houses by creating a pressure barrier to radon entry. This
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 an "active" radon system.
Testing:
The Final Word
The only way to
know if your 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 build 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 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 to 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 Information
Detailed model
building standards, architectural drawings of radon systems, and
fact sheets on alternative radon installations are available from
EPA at no charge by phoning 1-800-55-RADON or by visiting the EPA
website at www.epa.gov/iaq/radon.
Your builder can
also obtain information on radon-resistant construction techniques
from the National Association of Home Builders - "Building
Radon Resistant Homes: A Builder's Independent Study Kit."
A growing number of
municipalities located in areas known to have a high radon
potential now require or recommend that passive radon systems be
installed in all new houses. Contact your State Radon Office (State
Radon Contacts)
to
determine if you are building your new home in such an area.
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die each year of radon-associated lung cancer. According
to the EPA, elevated levels of Radon gas affects nearly one
home in fifteen. The risk is compounded dramatically with
the length of exposure to Radon and increases if the occupants
are smokers. 