radon

Yikes Paul -  Maybe you should be attaching a vapor barrier to the floor of the house. 

So I set the monitor on my desk - near my computer.  6.9

So my feet are probably in the radon soup but my pie hole is in much better shape.

What can we do to prevent tracking atomic waste into our homes should WWIII come along?

Metal roofs and no carpet are a good start. Easy to decontaminate.

Right now, try not tracking herbicides, defoliants and 24D into your homes and if crop dusters are around .. close your windows. We have a leased out field and get unannounced crop dusters in on top of us. Our Quarter Horses with colts use to go bananas .. horse pens right next to the bean field. Giant Corn Choppers .. two or three in a staggered row .. about the same thing .. "fear wise."

Park a brand new diesel dually on a center pivot track and think you will be back before the pivot arrives and find your new truck looking like a pile of junk.

Get too far from the Stone Age ..

Just happened to stumble on this thread.  Paul, you are at an incredibly high reading.  You are creating a vacuum in your basement and sucking the Radon through the slab floor.

In order to get the Radon out you have to cut a hole in your concrete slab, get to the gravel, install the duct and blow it out a window or hole in the foundation 24/7. low volume fan works fine. That is the standard remediation. 

We live on top of one of the bad Radon prongs in NY.  We tested back in '88 before we bought the house and we were under the EPA level, for what that is worth.  The levels do change every six months and the testing was a pain as you had to leave canisters out for a few days then send them to a lab.  I think we are going to get the meter now that I know it is available.

According to what I read you are not safe if even on the second floor of the house.  The particle enter your lungs and then kind of explode 20 years later.  Natural, fully-organic decomposition of a killer. 

Good luck.  Take it seriously.



Al

be concerned about that paul
the tricky thing with radon isn't the radiation from radon-thats pretty tame
but
the final decay product of radon is lead in a perfect form to be absorbed through your lungs any time you stir the dust up off the floor

on the other hand according to my environmental science text the risks are still pretty low so long as you don't smoke too even at high levels you remain under 1% increased risk for lung cancer

Thank you all for this post! I hadn't even considered Radon in my wild imaginations while planning/daydreaming about my future home... I live on a granite mountain.

Feral

Radon might actually prevent lung cancer:

Exposure To Low Levels Of Radon Appears To Reduce The Risk Of Lung Cancer, New Study Finds

ScienceDaily (Mar. 26, 2008) —

Exposure to levels of radon gas typically found in 90 percent of American homes appears to reduce the risk of developing lung cancer by as much as 60 percent, according to a study published in the March issue of the journal Health Physics. The finding differs significantly from the results of previous case-control studies of the effects of low-level radon exposure, which have detected a slightly elevated lung cancer risk (but without statistical significance) or no risk at all.

The study, undertaken jointly by researchers at Worcester Polytechnic Institute (WPI), Fallon Clinic, and Fallon Community Health Plan, is the first to observe a statistically significant hormetic effect of low-level radon exposure. Toxins and other environmental stressors (including radiation) that have a beneficial effect at very low doses are said to exhibit hormesis (scientists believe that the low doses of toxins may stimulate repair mechanisms in cells). Home exposure to radon, a naturally occurring radioactive decay product of radium, has been thought to be the second leading cause of lung cancer, after cigarette smoking. Chemically inert, it can percolate out of the ground into basements.
The study was initiated and managed by Donald F. Nelson, now professor emeritus of physics at WPI, during the 1990s, a time when concern over the link between residential radon exposure and lung cancer was growing. Nelson says the aim was to try to establish what level of radon exposure actually correlated with significant lung cancer risk and to establish a safety zone for home radon levels. "We were certainly not looking for a hormetic effect," says co-author Joel H. Popkin of Fallon Clinic and St. Vincent Hospital in Worcester. "Indeed, we were stunned when the data pointed to that conclusion in such a strong way."
In the study, the exposure of 200 individuals with confirmed cases of primary lung cancer to radon was compared to the exposure of 397 carefully matched, randomly selected control subjects. All subjects were 40 years old or older and had lived in their homes for at least 10 years. All of the cases and controls were residents of Worcester County in Massachusetts and were enrolled in the same health maintenance organization, Fallon Community Health Plan.
The results were statistically adjusted for factors known to be correlated with lung cancer risk, including smoking, occupational exposure to carcinogens, and level of education. The adjusted results show that the odds ratios of developing lung cancer fall below one (the no effect level) at radon exposure levels within the range measured in about 90 percent of homes across the United States (0-150 Becquerel per cubic meter of air, or about 0-4 picoCuries per liter). The Environmental Protection Agency (EPA) recommends that homeowners take remediation actions when household radon exposure levels rise above 4 picoCuries per liter, based on the belief that radon exposure presents a linearly increasing lung cancer risk (a view not supported by the new study in the low-dose region).
In a statistical analysis led by Richard E. Thompson, associate scientist in the department of biostatistics at the Johns Hopkins University Bloomberg School of Public Health, two mathematical techniques were used to compute the odds ratios of developing lung cancer. They each showed a statistically significant lowered lung cancer risk—a reduction of as much as 60 percent--over portions of the 0-150 Becquerel per cubic meter range.
The results of the current study do not fall within the "linear, no threshold" (LNT) model commonly used to analyze radon's cancer risk (in fact, the current study calls into question the validity of that model). The model starts with cancer risks documented for exposure to high levels of radon (for example, by uranium miners) and extrapolates a considerable distance to risks at low levels (for example, for homeowners). In that model, the odds ratios of developing cancer rise linearly from one, beginning at a radon level of zero. The model has been used by the EPA to derive its estimate that 21,000 cancer deaths annually can be attributed to radon exposure, and also accounts for the common belief that there is no safe level of radon exposure.
Donald Nelson says the differences in the outcomes of this and previous studies may be attributable to key elements of the new study's design. For example, he noted, care was taken to place radon monitors (for yearlong measurements) in areas of the home where the subjects spent the most wakeful time. Monitors were also place in the subjects' present and former bedrooms and on any other home level where they spent as little as one hour per week.
The subjects' exposures were then obtained by weighting the measurements according to the time typically spent near each detector. The results were further adjusted to account for how subjects' home use changed with changing lifestyle (for example, transitioning from full-time employment to retirement). "Our analysis shows this to be an important improvement over exposure measures used by almost all other studies," he said.
"It is important to note," Nelson added, "that these new results do not dispute the lung cancer risk associated with higher levels of radon exposure experienced by uranium miners. Nevertheless, the results represent a dramatic departure from previous results and beliefs. Of course, a single epidemiological study is seldom regarded as definitive, so our results point to the need for new studies using our techniques."
Nelson also noted that the study revealed a dramatic correlation between level of education and lung cancer risk. Subjects who had at least some college education were found to have only 30 percent of the lung cancer risk of those with less than a high school education. "While education has been found to be an important correlated variable in many health studies," he said, "this is a particularly striking and statistically significant result, one found after smoking, job exposures, and radon were statistically adjusted for."
Adapted from materials provided by Worcester Polytechnic Institute.

Wikipedia's entry on Radiation Hormesis:

http://en.wikipedia.org/wiki/Radiation_hormesis

Radon's a big issue around here as we're on granite ledge here in Vermont. Our old farm house was over 6 at times. Not good. I looked at doing mitigation but the cost was outrageous. Better to throw the house away. When we built our tiny cottage I built it with this in mind so we are both buffered and get lots of fresh air exchange.

"The solution to pollution is dilution" (and not having radon to begin with)

Cheers

-Walter
Sugar Mountain Farm
Pastured Pigs, Sheep & Kids
in the mountains of Vermont
Read about our on-farm butcher shop project:
http://SugarMtnFarm.com/butchershop
http://SugarMtnFarm.com/csa

paul wheaton wrote:So I set the monitor on my desk - near my computer.  6.9

So my feet are probably in the radon soup but my pie hole is in much better shape.

I've been a missionary in Japan for the past ten years, and now my wife and I thinking of moving back to Texas. I'd like to buy my own little piece of dirt and build a mortgage-free home on it myself. And I'm very curious about the "hobbit homes" I've come across online. However, building "earth sheltered" quickly made me wonder about what the radon risk might be...

So Paul, I found your forum through a google search for "cob house radon risk." And after reading through this forum, I see you've left us hanging. What happened with your radon problem in the basement?

I bet I'm not the only one who would appreciate an update!

paul wheaton wrote:So I got back.  And we hooked up 60 feet of eight inch duct to a pretty impressive eight inch duct fan.  The duct was laying on the floor near the worst spot.  We ran it for about four hours.  The duct went about ten feet away from the building on the outside. 

We reset the meter and it takes two days to come up with a reading.

This morning it reports:  53.1  - it went up!

http://www.youtube.com/watch?v=4WI4f_EK22E

Paul I think what's happening is that you're actually sucking the gas into your home by pulling air out.

The idea of air changes being good for things like radon is kinda kidding one's self. Think about it, if you're changing the air enough to make the problem as negligible as the air outside you basically need to be outside. Once you start adding walls a roof, windows and doors you're talking about massively reducing air change in an area even 10 ACH is WAY less then the same area outside. When you have 6,7 or 8 ACH your creating a funnel for the gasses to accumulate. Reduce that number to .6 and your simply not allowing the gasses in, that's why HRVs are used to CONTROL your air changes . Air and vapour permeable vs air drafting are two totally different concepts.

Personally I don't like crawl spaces for a ton of reasons; they don't help your heating, critter or radon mitigation. basements have their issues. sealed pads are the most practical option for building. Basically the earth is a powerful beast and you can't fight her and expect to win. If the earth if giving you a soil that has challenges like frost, radon, etc then the deeper you go into that earth the more she will make you work to live in it. So if you're in a climate and or soil condition where radon is an issue being in the ground is kinda like playing with fire. Its the age old one size does not fit all.

I came out of school thinking that Radon was an overblown concern mainly because Scandanavian countries had higher action levels than the US and the Euros are known for being quite cautious about health concerns and perceived threats. Things have changed since then and most countries are beginning to lower action limits to the World Health Organizatons recommendations of the equivalent of 2 picocurries which is half of the EPAs current level. The amount of ongoing research continues to pour out and most of it is too convincing for me to argue with.

As others have said, the most likely reason Paul increased his level was he put the house (lower levels in particular) under negative pressure. Conditioned structures tend to operate under negative pressure without other influences and the air will come in through the bottom cracks and holes in a house and make its way out the cracks and holes toward the top of the structure. You can probably forget about trying to drain away radon based on its heavier than air characteristics as others have pointed out.

Yes, structures that are built further into the ground will have a higher risk of ellevated Radon. However, a proper mitigation system will easily overcome this concern. Homes should have Radon mitigation systems whether above grade or not and the benefits of building into the ground depending on the site and construction goals shouldnt be overlooked by the poor radon mitigation details of other projects.

The best radon mitigation systems will avoid an active fan!

Like so many other things, radon mitigation is always easier with new construction. Putting in a passive system is usually pretty cheap and you can always arrange to hook it up to a fan should you find it not to be performing enough on its own. On our homes, we install an interior perimeter of perforated PVC in the gravel layer. It exits below the slab at the low point and elbows up to a solid vertical vent stack at the high point (on perfectly flat sites the pipe would be level). This setup is performing double duty as sub slab drainage and radon vent. The detail Iam in flux about is whether to carry the vent stack up outside of the building envelope or inside. Ive been doing it outside to avoid the two building envelope penetrations but it would arguably perform better run up inside as the heated space would help drive the stack effect. The tricky part is the vapor barrier seperating the gravel from the slab or floor. Its tricky to get airtight and is one of my favorite applications for sprayed closed cell foam because is takes care of air-sealing and insulation.

As for COB walls performing better for radon mitigation, thats very unlikely. The most proven ways other than a properly installed passive system involves active mechanical ventilation. Supply only ventilation is probably better than exhaust only ventilation for the postive pressure vs negative pressure reasons. A balanced system (ERV or HRV) would certainly help and having the ducts to distribute and exahuast the problem areas would be a major factor in its effectiveness to mitigate. Some existing homes have so much radon that they can only be mitigated by a dedicated sub-slab exhaust fan which is a shame because a layer of gravel and properly placed drain pipe could have made all the difference in avoiding one.

Your venting is causing more radon to be pulled in from the ground. You need to do something to seal the walls so the Radon can't penetrate. That is what radon specialists do they seal the crawlspace or basement. I don't know what they use.

This is an old thread but one aspect of radon is completely absent. Radon is also found in well water, particularly from drilled wells. Once the water enters your house it outgasses and enters the air. Radon in drinking water has a much smaller chance of causing stomach cancer than airborne radon causing lung cancer so it is generally given less attention.

In the U. S. each state can modify the EPA radon guidelines so you need to check locally to see what the rules and recommendations are. Here in Maine the state government is more conservative than the federal government and recommends the testing of water for radon in every home. The federal guideline is to only test for radon in water if the radon air levels are high. There are treatment systems to remove radon from domestic water if your levels are high.

You can get radon in air test kits from retail stores such as hardware stores and take the sample yourself, unless you are selling your home. At the time of real estate transaction Americans are required to hire a trained, registered person to take the sample or set out a testing device which gives the results directly.

Jim