Radon Testing in Basement

I have done it several times and will do it again very soon. We already have non-powered radon vents. Powered vents are not too expensive to install if your have structural steel or wood floors, if not the vent pipe is place in the gravel below your slab.

Spence:  How did your tests come out?  Living in coal mine country, I have thought about doing this myself.  I had an office in the basement for 25 plus years.  Now, the old office will become my layout room.  How do you conduct the test?  Do you get the results yourself, or, do you have to send the test out?  

 

Bob

I've done the testing and gotten between 9 and 12 uC per something. Four uC is supposed to be the max allowed. I read that the radon issue is largely driven by the radon elimination industry and errors in testing are common and the result of the fact that the testing has to be done over a very long time, not just a few days. What I read said that the dangers of radon can be cut in half by a ceiling fan to cause the charged products of the radon decay (which are the real issue) to adhere to surfaces in the room instead of the air you are breathing. I forget the link, but Google probably can find it for you.

Here in Southeast Wisconsin we have what is called the Niagra Escarpment. It goes up through Green Bay and east through the Great Lakes (O & E), and ends in Rochester, N.Y. We call it the ledge here in Fond du Lac. Anyone that wants to build a house on the ledge has to have radon piping put in. This doesn't answer your question, but I thought it was interesting enough to pass on.

Bob you can buy the test kit at either Lowe's or Home Depot. You just place the canister I forget whether it's one or two somewhere in the basement it will explain it to you and then after a weeks time you mail it away and they mail you the results. My results were a little high but nothing to worry about. The problem with my basement is there is no Fresh air that gets in there.

Radon is hit or miss in my area of Pennsylvania, underlying geology here is heavily fractured shale and limestone, can very permeable for radon. I tested my home when I moved in 3 years ago and it was > 19 pico-curies. A draft induction system was subsequently installed - level is now < 2.

Oh...so it was pC not uC for me too.

Radon here is about the same hit or miss. We moved into a new home last fall, it was professionally tested and readings were <1. The house across the street was built after ours (finished in Nov '13) and they had to have the removal system installed, sump pump sealed, etc. Don't know what their test reading was? We live in a cul-de-sac of 5 homes and that is the only one with a removal system. There are also a few other homes in the neighborhood with removal systems installed, some new some up to a few year old.

 

I was just curious, since yours was originally too high and is now <2 with the removal system, how often do you need to re-test or is re-testing even needed if your levels were low to begin with, or you already have a removal system? Did they tell you anything about that when the system was installed?

 

They tested our house for 48 hours with some kind of blower machine on a stand in the basement and said the test had to be done for 48 hours minimum. I have heard some things similar to what other posters have said, that the testing can produce false readings, has to be done over a long period of time, you can test positive one time and not the next, etc. Not sure what is right or wrong?

Mine was 7.3 during our home inspection.  We pushed for remediation cost (locally $1400. then) at settlement and it was mandated for transfer of title.

 

]I use a radon meter continuously and have been able to keep it at 1.2.

 

I have been told that readings need to be taken at a point 2' off the wall and 2' off the floor near the lowest point of the basement preferably near an open sump.

 

I installed my own system connected to a sealed second sump for French drain atmospheric  extraction and the reading settled down to  1.2 within 3 days and that was 7 years ago.

 

Radon validity is not based on subjective convictions.

 

 

 

We put one of those test kits in our basement and forgot about it. Probably has cancer by now so I'm not gong near it!

 

We also had the sellers install the radon removal equipment in the basement of our house, here in central IL. When we signed the paperwork through our real estate agent, with the offer, back in 2012, we worded it that the offer was conditional to the successful completion of the radon test. The company that did the inspections left the test device in the basement for the specified days with instructions that no one goes into the basement. When it came back as higher than allowed, this inspection company informed the sellers & us. Although the inspectors were qualified to install the radon mitigation system, they couldn’t due to conflict of interest. The sellers were initially reluctant to do it but after contacting a few companies, it cost them a little over $1000 to install it.

Regarding the issue whether radon is bad for your health or not, the answer depended on the age of the people I talked to. Since this was our first house I consulted our friends, relatives & colleagues. The older people didn’t seem to worry much about it. Their general response was along the lines of – I lived in my home for over 20 / 30 years & I didn’t get lung cancer & I am not going to worry about it. The younger homeowners either had piping installed when they built their homes or had it installed by the people they bought the house from since Radon apparently was the second leading cause of lung cancer in this country.

I also discovered that if you are buying a condo in a high rise building above the 2^nd or 3^rd floor you didn’t need to worry about radon systems.

These are just my opinion,

Thanks,

Naveen Rajan

radon testing with the canisters sold to consumers are very inaccurate. they take a small sample over a very short time. radon levels change with water table fluctuations, interior buildings pressures to name a few. the only acurate testing involves a metering sensor that runs for at least a month or more and makes a graph of daily fluctuations. you can then average these out and get a truer reading. this should be done at different times of the year as temperature changes in the climate over the year will also affect the readings. as far as venting, it is good for the basement also by having air circulating under the slab it will keep the moisture down even if you do not have a radon problem. always try to not have negative pressure in your house as this draws the radon into the house as well as carbon monoxide from flues. older houses are pretty leaky so running exhaust vents may not be a problem, but in newer tighter houses, even a small kitchen hood exhaust will cause negative pressure. you need to have an intake of fresh air from the outside to balance this out. finally I have to say that the limits set by the government are educated guesses, exposure is different with each individual. my standard is 0 ppm with or without mitigation. if you can't achieve this even with venting you have a problem.

Before I finished my basement, I had the radon tested.  It was around 9-10.  I had radon remediation done.  It dropped my radon down to .3.  With the amount of time I spend down there, I  wanted to make it as safe as possible.    The remediation was around 1000 and well worth it.

With the permission of the moderator(s) and you folks, let me add my advice on the radon issue.  I spent about ten years of my scientific career at Lawrence Berkeley National Lab studying radon and, in particular, how it enters houses and how to best mitigate problem houses. I did not have then (nor do I now since I'm retired) any commercial affiliations or interests regarding specific test kits or mitigation systems.

 

For the most part, the previous posts have it about right - radon enters houses mainly through surfaces in contact with the soil - basement walls, floors, etc. (slab-on-grade houses aren't immune either).   Basically, houses suck and that draws air into the house, some of which comes in through the soil and that soil gas transports the radon that is naturally there.  The main driving force in house with elevated radon concentrations is the natural - but very slight - depressurization that occurs in buildings due to the thermal stack effect (especially in the winter) and wind loading on the building shell. Indeed, in a tight house, kitchen and other exhaust fans can add to that depressurization, but they aren't on long enough to generally create a radon problem and besides there is a significant benefit to running them when cooking (another topic for another time...).

 

Geology plays a strong role in determining whether a house or an area is likely to have a radon problem, as does the permeability of the soil, the construction details of the house, etc.  We studied a number of homes in NJ, PA, FL and in WA (near Spokane) and found houses side by side with large differences in indoor radon concentrations.  My advice would be to contact the local (county or state) health folks and ask whether radon is a problem in your area.  At one time, several states, like NY, NJ and PA (and others), did a fair amount of radon mapping to attempt to find areas where the possibility of having elevated indoor radon concentrations was higher.

 

Testing is relatively cheap - but as some have already noted - some tests are barely worth the powder it would take to blow them up.  The best testing procedure is to use long term devices that provide an average value over several months - even up to a year.  What counts in terms of the health effects associated with radon (its the radioactive decay products of radon - themselves radioactive - that are the source of the lung cancer - but radon is easier to measure) is your cumulative exposure over a long period of time.  The guideline air concentration used by the Environmental Protection Agency is 4 picoCuries per Liter of air - that's not a 'bright line' number - above which your are immediately unsafe.  Again, what counts is a long term average in terms of comparing to the 4 pCi/L.  I don't know what Home Depot or Lowe's sell for test kits - its not an issue here in the SF Bay Area so they don't stock them to my knowledge - but there are devices that will integrate over weeks or better, months.  I would be very skeptical of a radon test that is less than a few days long (unless the results came back very high - greater than 20 or 30 pCi/L).  There are seasonal - even daily - differences (winter usually higher than summer) that short term tests simply don't account for.  Besides, you want the test conditions to be how you live in the house/basement - not arbitrarily closed off.

 

If you are concerned, I'd get a couple of 'long term' test kits and put one in the basement and one in the living area of the house for the next couple of months and follow that with a similar set of measurements over a longer period of time.  If that initial test is above 8 - 10 pCi/L, then you might want to talk with a mitigation contractor - if below that, then I'd wait for the longer term test results.  My advice is probably more conservative than what your realtor would tell you to do - perhaps even the local authorities or your spouse, so its FWIW.

 

In terms of mitigation, yes sub-slab suction is the best way to go - some passive systems have been effective, but the fan-powered ones seem to be more robust across a range of houses, soil conditions, etc.  I don't know what the current costs are for hiring a radon mitigation contractor, but $1k to a few thousand was the range several years ago.  There are other products - like air cleaners and ceiling fans - that make claims about reducing radon risk, but in our experience, they are mostly ineffective.  Keeping it out is a better way to go - though it should be noted that there is no such thing as a radon free house - outdoor air contains a few tenths of a pCi/L and earth-based materials (concrete, etc.) emit radon from the naturally occurring radium and uranium widely distributed in the earth's crust.  The average radon concentration in the US housing stock is around 1.3 pCi/L

An authoritative response!  Thanks, Rich.

 

in my part of PA they build with the piping already installed.  Not surprisingly, after testing a couple years later, we added the fan.  The trains are set up in the basement.  

 

Now, how about the radioactivity coming from granite countertops?

I was horrified when after our house was sold at the beginning of the financial collapse in May 2009, radon was discovered in the basement. The house was on ledge, which probably was the cause. The reading was slightly over 4. The realtor wanted to retest, but I said we'd install the fan and piping, about $1500. He said that he'd pay for the test, but I was more concerned the possible result, not the cost. Our other offer for the house was about $$7000 lower.

I live in Northeastern Pennsylvania.  About ten years ago I did a test from Lowes and it was sky high in my new home.  I then hired a geologist who confirmed the test.  He said it was the same as four packs of cigarettes a day.  Wow.....so we had it mediated and the cost was about a grand.  Worth every penny as the system works well and not a problem to this day.

John

I think anyone who lives in coal country, Pennsylvania, Ohio, West Virginia, is probably more likely to have a problem than in areas where the underground has not been completely devastated by mining.

Geologist showed me an underground map and the source undulates up and down underground.  You can have a neighbor with a low reading and then you can have a sky high out of control reading as we do.  Several of our neighbors are very high and some low to normal.  The underground anatomy explains this.

I'm hoping with enough Radon exposure I can become a mutant with super powers and save people from green goblins and Asgardian gods. 

After the induction system was installed - it was tested by the contractor, and then again by the home insector, and I tested it a year later, all with low results. Probably a good idea to do it every few years.

Good idea for anyone with a basement to get the radon level tested. We did at time of construction and there were no issues.

Would that require a shell and eating a lot of pizza? I have spent enough time in basements over the years that I should at least have a nice shell by now.

 

 

Thanks, I was considering another testing in another year or so, especially since the house across the cul-de-sac had high readings. I guess I'm kind of with the older folks another poster mentioned, I have spent a lot of time in basement's for many years (work shops, trains, computer room, rec room, pool tables etc.) and all that started when I was a kid in the '50s, long before anyone ever heard of radon. At least before I had heard of it anyway. Now that I am aware of it, I do sort of feel a need to monitor it more closely.

A couple of 'final' thoughts regarding radon mitigation - its probably a good idea to conduct occasional, long-term testing of a house that has a radon mitigation system installed - the key being 'long-term' - such as six months to a year.  Another thing to consider would be to install a pressure gauge as a way of monitoring system performance.  Typical operational pressures - as measured in a suction pipe that passes through the basement floor - are in the neighborhood of 1 inch of water gauge (or 250 Pascals - Pa - if you are tuned into metric).  That pressure, by the way, is negative with respect to the basement air pressure.  I don't know whether installation of such a gauge is required of mitigation contractors.  Sometimes folks use an oil manometer, but they can run dry if ignored.  A better - slightly more expensive - choice would be a mechanical pressure gauge capable of measuring negative pressures and calibrated in the range of 1 to 2 inches of water (or 250 to 500 Pa).  There might be some fluctuation in the pressure if the soil gets very saturated or in high wind conditions but long term, it shouldn't change much.  If it does, then contact the mitigation contractor and/or do another radon test.

 

Lastly, a previous post mentions granite countertops as a source of radon - which indeed they are - as is any other material with an earth origin (e.g., concrete).  Typically, the emission rate of radon from these materials is simply too low to account for any sort of elevated indoor radon concentration under normal house conditions where the ventilation rate is also typical.

Near my crocks I keep this Radon meter on 24/7.

 

It is located under a lift out bridge between two modules.

Tom T; where did you buy that radon alarm?

You had me seriously worried with uCi levels. 

 

I've spent the last 30 years working with Radium in my labs (1st daughter decay product is one of the Radon isotopes).  Fortunately the half-life of the one I work with is very short; however, the ventilation and filtration requirements are quite significant when working with volatile alpha emitters such as Radon and others... 

 

 

The one I have came with my radon remediation system.  The same meter is sold by many companies for $129.

 

Just Google "radon digital meter".

 

I elected to seal the existing crock which then can be used to collect radon via the French drain and stone bed.  Then  installed a new unsealed second crock to collect any incidental surface water.

 

Each crock has a 110 ac pump and a 12 volt dc back up Watch Dog pump.

Tom; thank you, just bought one.