With a headline like that, I had to read the article this morning from our local television station. Radon can be a big problem in your homes, but what do you do if there is a problem? If you live in a new home and it was built “right,” then there is a radon mitigation system built in ready to be activated. If you are living in a home where this was not thought through in advance, then you have a little more work to do, but it is not a big project. So let’s review some facts:
Radon comes from the natural radioactive decay of radium and uranium found in the soil. The amount of radon in the soil depends on a complex chemistry that varies from one area to another. Radon levels in the soil range from a few hundred to several thousand pCi/L. The amount of radon that escapes from the soil to enter the house depends on the weather, soil porosity, soil moisture, and the suction within the house.
First, how does Radon get into the house? In a typical home, war air rises, making houses act like chimneys. Since in the past we largely left our attics unconditioned with an access to the space that is usually not air tight, homes essentially act as large chimneys sucking air up and out through the attic. This air movement in a home creates a small suction at the lowest level of the house (basement, crawl space, first floor on slab) pulling the radon into the home from the soil. The smallest pin holes in your lower level will give enough space for radon to enter the home. If your home is built tight, this will greatly reduce the possibility of air / radon entering from the basement and exiting through the attic. If your home is built to code, then you probably have a home with plenty of “pin” holes for radon to enter. If the test is done when the soil is saturated, then there is even more exterior pressure pushing radon into the home.
So now what should you do? The first step is to get tested. I would recommend getting a home test kit that you can do yourself and send off from a local hardware store. These tests are not as reliable as a professional test, but will give you an idea of where you stand. If you can schedule this for a week when you are on vacation, then you will get the best results. If you find that the radon levels are border line or higher with this test, I would strongly suggest getting a professional test.
If your test indicates that you need a mitigation system, then I would recommend installing one of good quality that is durable and energy efficient. You should have your contractor that installs the system perform a test to show that the levels have been reduced to an acceptable level before issuing payment for the project. There is no way to know if you have a problem without testing. If you have a basement that has few or no windows or ventilation and the air is rarely disturbed by people moving in the space, your test will almost certainly come back positive. If your HVAC system return is in the basement, then you could have a radon distribution system built into your home.
A mitigation system is not complicated, but it does need to be installed right to work effectively and not cause a bigger problem in the future. First, the system is essentially a pipe that runs from below your slab through your roof. There should be a fan installed in the attic (or at least above your living space) that sucks air out of your home through the roof. You want the vent to exit the home away from windows, doors, or deck where people might breathe it in. The pipe will feed from a reservoir or suction pit should be deep enough that it is the low point in the house. Then I would suggest making your basement / crawl space a conditioned space with positive pressure to help push any gas that gets in out. This should be done even if you don’t have a radon test for energy efficiency and indoor air quality in your home, but it is worth saying again here.
A radon mitigation system rough- in should be a standard feature on all new homes – in my opinion – and all homes should have an active system installed if needed.