Radon on a slab.

[netnews]

Is radon an issue with homes built on a slab?

I would not think so, because (from my limited understaning) any properly constructed slab should have an integral vapor barrior. Thanks for your thoughts.

[Phisherman]

Radon is a concern. The radon levels can vary by season. It would be a good idea to test areas in a home, especially those areas which more time is spent. I had a contingency to the purchase of my home for a satisfactory reading of radon on all levels, including the basement which showed the highest (but safe) level. I live in an area of the country where radon levels are typically higher than normal.

[JohnB]

In 1988 we made an offer on a house contingent among other things on a satisfatory radon test. The house is built on a slab and it failed the radon test, so the seller arranged for remediation. I hope it worked because I am now in the room which failed the test. The house is cut into the side of a hill with ground floor entrances on two levels. Some of the radon may be coming through the cement block walls rather than through the slab.

[Phisherman]

Why not have another test or two done? Space the tests 6 months apart. Each test should be about $20. There is a rubber-cement type paint you can apply to the cement blocks to reduce the radon level. Radon is particularly harmful to tobacco smokers.

[spamfree]

Radon is a joke. Just another way for someone to make a buck by scaring people. People have lived on this planet for millions of years, and it was not till the 1980's when some whacko decided he could make some fast bucks by scaring the public. There is no such thing as Radon !

[Dave]

I agree! It is nothing but a get rich quick scam for those pushing it. What a joke. Like PT Barnum said there's a sucker born every minute!

[SMF]

Isn't radon the second leading cause of lung cancer next to smoking?

(from medical literature)

[Jeff Cochran]

It can be.

How do you know your slab was properly constructed? How do you know the vapor barrier hasn't deteriorated?

Jeff

[Bruce]

Hope this does not get double-posted. Had a problem when I tried to post just now.

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Radon can be present in any home of any type of construction. A vapor barrier in the slab is not a barrier to radon.

Painting the slab will not prevent radon from entering the home. Cracks in the slab will allow radon to enter the home and so will plumbing penetrations (e.g., toilets, tubs, waste piping, etc.), joints between the slab and foundation wall, sump pits, etc. And even if all these cracks, joints and penetrations are sealed radon can still pass through concrete because concrete is not impermeable.

Every home should be tested for radon. A home that has had a radon mitigation system installed should be tested (how else will you know if the mitigation system is lowering the radon levels below 4 pc/l?). EPA recommends that every home be tested every two years.

Consider conducting a long-term radon test to get a more real-world reading of the radon levels present in the home. A long-term test can be anywhere from 90 days to one year. A one-year test is more meaningful because it is not as affected by seasonal highs and lows as a shorter test. You can buy a long-term radon test device (alpha track device) and conduct your own test for under $50. Make sure you follow the EPA protocols so the readings are meaningful.

Radon is the second leading cause of lung cancer behind smoking. EPA says over 20,000 people die in the US annually from lung cancer caused by radon. If you smoke your risk associated with radon is increased anywhere from 15 to 20 times that of a non-smoker. Children are especially at risk to radon. Visit

and follow the radon links to learn more about radon.

I am a NEHA (National Environmental Health Association) certified Residential Measurement Provider so I do know what I am talking about.

[Bruce]

Radon can be present in any home of any type of construction. A vapor barrier in the slab is not a barrier to radon.

Painting the slab will not prevent radon from entering the home. Cracks in the slab will allow radon to enter the home and so will plumbing penetrations (e.g., toilets, tubs, waste piping, etc.), joints between the slab and foundation wall, sump pits, etc. And even if all these cracks, joints and penetrations are sealed radon can still pass through concrete because concrete is not impermeable.

Every home should be tested for radon. A home that has had a radon mitigation system installed should be tested (how else will you know if the mitigation system is lowering the radon levels below 4 pc/l?). EPA recommends that every home be tested every two years.

Consider conducting a long-term radon test to get a more real world reading of the radon levels present in the home. A long-term test can be anywhere from 90 days to one year. A one-year test is more meaningful because it is not as affected by seasonal highs and lows as a shorter test. You can buy a long-term radon test device (alpha track device) and conduct your own test for under $50. Make sure you follow the EPA protocols so the readings are meaningful.

Radon is the second leading cause of lung cancer behind smoking. EPA says over 20,000 people die in the US annually from lung cancer caused by radon. If you smoke your risk associated with radon is increased anywhere from 15 to 20 times that of a non-smoker. Children are especially at risk to radon. Visit

and follow the radon links to learn more about radon.

I am a NEHA (National Environmental Health Association) certified Residential Measurement Provider so I do know what I am talking about.

[Ron Hardin]

If you can increase the risk 20 times, it can't be very big to start with, can it.

[Bruce]

Well, Ron, you will have to be the judge of that. Why does the risk have to be small if you can increase it by a factor of 20? I don't follow your logic.

[George E. Cawthon]

Good point but then 20,000 people dying per year isn't much. It certainly doesn't keep people from riding in automobiles. Of course if you smoke, why would you pay ANY attention to radon? That's kind of like jumping off a cliff and worrying about whether your shoe laces are undone and you might trip.

As for the practical, in most instances a little ventilation will solve any radon problem.

[Laptopuser]

A physicist friend of mine is actually a radon expert. His web page offers a lot of good information, some of it specific to our region but much that would apply anywhere. Take a gander:

-Derek