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10 Reasons to Test and Re-Test for Radon

Syracuse Radon Test KitRadon levels and radon test results in homes can vary greatly for a number of reasons. As a home inspector I always recommend every homeowner do a radon test when they move into their new home, even if a radon test was done as part of your home inspection. In some cases, even if a recent radon test has come or comes back low, below 4 pCi/L or even below 2 pCi/L, it may be a good idea to retest your home for radon.

Below, I have 10 good reasons why your home’s radon may actually be significantly higher or come back higher at a future date. I strongly urge you for one or more of the following 10 reasons to re-test your home for radon, whether your are in the process of buying a home now or you are living in a home that has previously been tested. Most likely more than one of these reasons will apply to your situation.

10 Reasons Why You Need to Test and Re-Test for Radon

1.  If your radon test was conducted as part of a real estate sale, it is not uncommon for the testing protocols to be violated either by accident or unfortunately sometimes on purpose. I have seen this happen time and again. For this reason it’s always good for new homeowners to do a radon test after they move in, even if there is a radon mitigation system present; the homeowner can hire out or do their own test when they are in control to ensure proper radon testing protocols are met.

2.  If your radon test was conducted during warm weather, we recommend re-testing at the coldest time of the year. Radon levels can vary significantly between seasons and varied radon levels are to be expected. Generally radon levels in homes are highest during coldest part of winter and could be double or more when houses are closed up tight, heating systems are running and the ground around the house if frozen.

3.  Changes to the home can raise the indoor radon level. If you make any structural changes, add additions, or have a new or different type of heating system installed you should re-test for radon. If you have new windows, new siding or additional insulation installed or have energy saving, air sealing, these improvements can increase the amount of radon trapped in the home. All of these are reasons to re-test for radon.

4.  If your radon test was conducted in a drafty basement but the upper floors are very tight or newer construction it is most likely wrapped in Tyvek or house wrap, air sealed and well insulated and it would not be unusual for the upper floors to have a higher radon reading than in the basement, especially a second floor during winter months. I have found this to be the case in some newly constructed homes with unfinished basements the first floor with higher radon than the basement and the second floor with yet higher radon than the first floor.

5.  If you tested radon on the first floor but later start to use a lower level, such as a basement play area or finished basement room and have not tested the basement level, it could have a much higher radon concentration than the first floor. If so, you should conduct a test in the basement.

6.  Often test radon test kits hang from the ceiling or test are placed up on shelves or tables. Please be aware that radon level could be three times as high for a test placed near the ceiling as compared to one placed 20 inches above the floor of the same room. So you should consider placement of test devices in relationship to the occupants use of the room; if babies, toddlers or pets are present which spend much time near floor level it would be a good idea to test at the lowest level – EPA radon testing protocol for the height of the testing location states:

“The detector should be at least 50 centimeters (20 inches) from the floor, and at least 10 centimeters (4 inches) from other objects. For those detectors that may be suspended, an optimal height for placement is in the general breathing zone, such as 2 to 2.5 meters (about 6 to 8 feet) from the floor.” (EPA Radon Testing Protocols)

7.  If your radon test was conducted during rapidly changing or stormy weather, or extended periods of heavy rain, the levels may change quite dramatically compared to normal either increasing or decreasing radon level, so much so, that If sustained winds of 30 or more miles per hour occur during a radon test, the test results should be discarded or have a statement that discredits the validity of the results.

8.  Continuous changes in household radon levels are considered the norm, much more so in some houses than others. The longer the radon test the more accurate the results. For the most accurate test results you may want to do a long term radon test of 6 months to a year. A year long test will provide a better overall real life average. Radon can even be cyclical from year to year also, for example, a lower average for a few years then raising to higher average levels for a few years.

9.  If the radon testing protocols were not followed a new test adhering to proper protocols should be conducted. For example, a continuous monitor placed in a crawl space or on the floor next to an open sump pit is likely to read much much higher radon levels than if it had been placed following the EPA radon testing protocols.

10.  Also, to get a good overall picture of the whole house radon levels, multiple tests can be conducted simultaneously in different rooms. Such test results would likely vary quite a bit on the average New York home and will give you an overall assessment of the radon in different parts of the home.

Radon tends to be allusive and difficult to pin down. If you live in New York its likely one or more of these reasons applies to your own situation. When there is reason to test or re-testing for radon, you should just do it. Radon testing is pretty simple and not expensive so just decide now to re-test your home and either confirm the radon is at an acceptable level or find out if corrective action is needed. If you find out your home’s radon is at or above the 4.0 pCi/L action level, then it is advised to take the needed action to correct it and keep your family safe.

I have seen this time and again where a second or later radon test reveals a significantly higher radon level than what was previously tested in a home. I would be interested to hear from you if any of these situations have applied to you. If you have further questions regarding radon testing or need advice on follow-up testing or test interpreting your test results call or email Tom Francis at 315-439-1103 or