No moisture barrier placed underneath the concrete

Q: I currently have my floor dug up in my kitchen. I’m trying to find a source of moisture after seeing dark stains in a few spots on my wood floor. So far we have found no leak, but there is moisture in the soil. We have discovered that there was no moisture barrier placed underneath the concrete. Would it be considered standard practice to place a moisture barrier under concrete?

Not sure how to proceed.

A: Concrete work is really out of the range of my expertise. I would think if the workers were aware before pouring the concrete that a moisture issue existed, using a barrier would have been a good idea. However, a moisture barrier can be used on top of the concrete to at least retard or slow down moisture transfer. This could include roll out membranes and even certain coatings applied to the concrete.

2 thoughts on “No moisture barrier placed underneath the concrete”

  1. I wouldn’t expect any problems. He could have done some tests to see if moisture is detected wicking up through the concrete. But if it is dry with no indications of dampness or mold I wouldn’t worry.
    Additionally, some of these mastic adhesives also serve as a moisture barrier, though I have no idea of what he used. If a significant moisture problem is present you probably would know by now or will eventually by cupping of the boards.

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