Thread: Radon levels off the chart.

I did a radon measurement last week and was shocked to find the reading on my Sun Nuclear monitor at 90.3 after figuring the calibration in. I told the agent that there may be a malfunction so I wanted to do another test with a different monitor. When I picked it up the reading was 93.6. Until now the highest reading I have seen was 17.4. The house is on a basement. The right wall is leaning in and has a crack about 1/2 inch all the way across and there are expansion cracks in the floor in many places. Other than that can anyone suggest areas that radon may be getting in and the fix for them?

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If there is a bath tub or shower in the basement, there is a large hole in the slab where the trap and waste pipes go under the slab. That can be a huge source of gas entering the house.

The house is likely just sitting over the right geology for radon. That's why you are getting much higher readings than you usually get. In my area, most radon levels (that are over 4.0) are in the 9.0 - 22.0 range. However, I have had many in the 50's and 60's, and last year did a house that was 160.

I've tested a few crawlspace homes that were in the 20's.

We have houses in PA that test in the 1000's. It mostly depends on what type of rock is below the house.

What did you use for a secondary measurement ?

Curious , Also do you know what the testing methods are that are used in the test equipment (again curious)

Is there an Uranium mine nearby??

Many years ago, while in South Florida (we didn't have much radon down there, but some) a friend of mine who got into the radon business tested a house for a relocation company, the owner was being transferred out West someplace (Arizona, maybe).

When the test results came back (this was before the continuous radon monitors), the results were in the hundreds, maybe 400-500. The relocation company asked for a retest to verify that reading.

My friend went back and did another test, and the results came back around 2 or something like that.

In trying to figure out why the difference and what was different, my friend realized that the lady was still living there at the first test, but not at the second test, and that she had some exquisite display cabinets which had ... a very extensive rock collection in them ...

Yep, she took the radon with her wherever she moved to. or, for her

I understand there are caves in Tennessee that are loaded with Radon gas, perhaps the home is built over one of them? You might check with the geological folks. Not a joke!

Jerry,
Let the agent know this may be a money making opportunity. There are mines around Boulder (MT.) used as.....radon spas. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2477705/

Originally Posted by Dwight Doane

What did you use for a secondary measurement ?

Curious , Also do you know what the testing methods are that are used in the test equipment (again curious)

I used another Sun continuous read monitor. My understanding is they sample the air each hour and record the Radon present in each sampling.

Originally Posted by Thomas McKay

I understand there are caves in Tennessee that are loaded with Radon gas, perhaps the home is built over one of them? You might check with the geological folks. Not a joke!

Most caves in TN have very high air exchanges due to underground rivers, streams and the chimney effect form high and low openings in them…. The original poster is from NC, not TN...

Originally Posted by Jerry Martin

I did a radon measurement last week and was shocked to find the reading on my Sun Nuclear monitor at 90.3 after figuring the calibration in. I told the agent that there may be a malfunction so I wanted to do another test with a different monitor. When I picked it up the reading was 93.6. Until now the highest reading I have seen was 17.4. The house is on a basement. The right wall is leaning in and has a crack about 1/2 inch all the way across and there are expansion cracks in the floor in many places. Other than that can anyone suggest areas that radon may be getting in and the fix for them?

I am Radon Measurement Certified in Texas and we don't have many basements here if any at all. We are in a low risk area for high radon levels, but have seen high levels as high as 19 here only a handful of times literally in 8 years. Causes of high levels you are experiencing can be from large storms. What has the weather been then lately. You know what we here in Texas have been getting lately! Just a another 2 cents. We use Sun Nuclear as well and the calibration chamber we have for our company is very accurate and when we get high readings, we set another unit to get the second opinion.

When you get a hinky reading do you charge for a second test to confirm the first or only if the second test comes in close to the first.

I was asked by a client if I recommended a Radon test on a slab and didn't have a supportable answer for her. I would think you a as likely to find radon gas in a slab constructed home as one over a basement or crawl space but.....

On rare occasions, radon comes from unexpected sources. Some twenty years ago in Aurora, CO, a relocation company ordered a radon test that came back in the twenties. Mitigation was done with no effect on the level. Finally they realized that the beautiful granite fireplace was "hot". The relo company replaced the fireplace and the level fell to below 4.

Originally Posted by Marshall Brown

When you get a hinky reading do you charge for a second test to confirm the first or only if the second test comes in close to the first.

I was asked by a client if I recommended a Radon test on a slab and didn't have a supportable answer for her. I would think you a as likely to find radon gas in a slab constructed home as one over a basement or crawl space but.....

First of all, you can have elevated levels in any house, basement, slab or crawlspace. A basement has the highest risk because there is more surface area of slab and foundation walls in contact with the earth.
A slab is next highest risk because the slab is in direct contact with the earth.
While a crawlspace is usually vented, if the radon levels in that particular area are high enough, it will show up inside the house. We have many homes with crawlspaces that have mitigation systems installed.
If its high, it's high.

My service area is a red zone, or highest likelihood of having elevated levels. After doing thousands of radon tests I have a pretty good idea where the hot spots are, and can advise clients about testing.

Regarding second tests.......the only time I might do another test is if I find a TAMPER, or a huge storm came thru during the test period, and I noticed unusual readings during that time period. If its a tamper, I let someone else pay. If its a storm or other weirdness, I usually will not charge for the re-test.