Question: Is there information available, such as research, case studies, and field experiences, that documents the long-term performance of polyethylene sheets used as vapor barriers beneath concrete slabs on grade? Currently, what little evidence I have indicates that polyethylene under slabs degrades over time. This is important, for example, if polyethylene used under a slab as a radon-abatement technique degrades.

Answer: We are not aware of any extensive research on the long-term stability of polyethylene sheets beneath concrete slabs. If anyone knows of such research or has had experience with degradation of poly sheeting, please contact us.