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Community and Q&A

Under-slab vapor barrier

BruceAF | Posted in Energy Efficiency and Durability on

The project I am working on has a 10 mil vapor barrier spec’d. It has come to my attention that standard 10 mil poly from the supply yard is not technically rated for under ground use as the content of the plastic may contain recycled material that will not hold up over time. A product such WR Meadows Perminator ( should be used (there are others out there). What do you think?

Secondly, does anyone have experience with Grace PrePrufe 300 self adhering under slab waterproofing?

Thanks for any feedback


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  1. GBA Editor
    Martin Holladay | | #1

    I haven't used either product. However, WR Meadows and Grace are both reputable manufacturers known for high-quality products.

  2. davidmeiland | | #2

    I have used Stego Wrap when a heavy duty product was needed.

    What would a self-adhering under-slab barrier be adhered to, and why?

  3. user-460363 | | #3

    I was going to go with something like Delta MS Underslab for our floor, which is dimpled and 25 mil, and should be pretty bulletproof. But probably not the cheapest option. It's going to be a radon barrier too, so I want no chances of it puncturing or failing. Hence the 25 mils.

    It says it's " Recycled high-density polyethylene, encapsulated between two layers of special virgin HDPE".

  4. BruceAF | | #4

    To David - you said: What would a self-adhering under-slab barrier be adhered to, and why? can watch the video here:

    The barrier adheres to the concrete from would be like spraying a TuffnDri on the foundation wall.


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