A radon barrier was placed using 6mil polyethylene sheets and sealed with silicon in at the seams. However, I do notice in certain spots a couple of drops of water underneath the sheet.

  • Is this okay? Will there be a mold damage or something and can it penetrate the barrier?
  • Shouldn't the moisture disappear over time?

In general I want to know if I should be worried.

1 Answer 1


It is absolutely normal. What you do not want to see is standing water under it. I have seen moisture under my plastic all the times I visited my crawlspace, mold has never been a problem. The idea is though to have no organic material like wood, grass, anything else that would decay, trapped under the plastic.

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