Radon Gas…The Silent Killer

Radon Gas Mitigation System on Exterior

January is National Radon Gas Action Month so it would be appropriate for us to talk about how it can affect you and your family.  You can’t feel, see, or smell it.  Silent but deadly, radon gas is known to be the second leading cause of lung cancer in the United States.  It comes from the ground, so unless your home is built on stilts, there’s a possibility you will have it.  According to the EPA, over 8 million homes in the U.S. have dangerous levels of radon gas.  So, what is the least expensive way to prepare for radon gas in your home?

There is no sure way to tell if you will have radon gas before your house is built.  In fact, I have built two homes right next door to each other…one had radon gas and the other did not.  So why don’t I just wait until my new building project is done to see if I have radon gas?  First, if you find out you have radon gas after your home or addition is built, you will spend significantly more money adding a radon reduction system.  It will cost you $500 to $1200 more if you add it to an existing home versus including it in the initial building design.  Not to mention that adding the system after the fact can be unsightly (see the pictures for a radon gas mitigation system added after the fact).

How do I include a low cost radon gas reducing system into my new building project?  The best and least expensive proactive approach is to install a passive radon gas reduction system.  Basically, you include a layer of plastic (6 mil polyethylene) under the basement or first floor slab.  You typically have 4″ of stone under this slab anyway, but if you don’t, you will want to add it (plastic goes on top of stone).  This stone layer allows for migration of the radon gas under the slab.  Next you will include a 3″ PVC pipe that will start in the stone under the slab (with “T” fitting embedded in stone) and will run vertically up through the house and out through the roof.  Ideally, this pipe will be centrally located in the house.  Then, you seal up all penetrations in the concrete floor with a polyurethane caulk.  This includes all control joints, pipe penetrations, the joint between the slab and the foundation…etc.  You will also want to seal any plumbing crock lids (i.e. sump pumps or sewer ejector pits or bath rough-ins).  The vent must terminate at least 12″ above the roof and be a minimum of 10′ from windows/doors.

Exterior Radon Gas Vent on Home

What will this passive system cost me for my new project?  In my experience, the actual cost of this passive system ranges from $250 to $350.  After all, you’re just adding some plastic under the floor, some PVC pipe, and caulk.  You might also want to include some money for an electric line to the attic in case you want to add a fan later.  This line will be much easier and cheaper to run before drywall goes up.

How do I convert a passive radon gas system into an active system?  If you test your home after construction is complete (recommended) and you find high levels of radon gas, you will want to convert your passive system into an active system.  This basically adds a fan in the attic attached to the PVC pipe.  This fan helps draw the radon gas out from under the floor and out through the roof.  The fan will cost anywhere from $125 to $175.  If you already have the electric line installed, the labor to install should be $100 or so.

How do I test for Radon gas?  There are many reputable companies out there that do testing.  Just make sure the company you go with doesn’t install radon reduction systems…due to the possibility of a conflict of interest.  I have seen too many contractors that use a given service to bring in other business.  Most people are honest…it’s the few bad apples that ruin it for the rest.  There are also many do it yourself testing kits that cost $20 to $50 and include lab testing and shipping costs.  I personally don’t have any experience with the DIY kits…although I have heard good feedback from friends.

What if my new home has a crawl space and a basement?  You will need two separate venting systems if your project has both a crawl space and basement or if you have a slab on grade and a crawl.

According to recent reports from the World Health Organization, radon gas is responsible for approximately 100,000 deaths worldwide each year.  This equates to about 15% of all lung cancer deaths.  In the U.S. alone, approximately 20,000 people die as a result of radon each year.  For this reason, you should include a radon gas mitigation system into your new project design.  For those of you who plan on staying put in your existing home, be sure to test your home for radon gas as soon as possible to make sure your family is safe.  To find out more about radon gas and how it affects you and your family, go to the U.S. EPA Radon Consumer Information site.

One last thought…be sure to implement a radon gas mitigation system prior to finishing your basement space as it will be much more difficult after completion.  If you’re in the process of planning a new basement finishing project, check out our helpful videos and basement finishing tips under the Resources tab at our main site.

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