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Community and Q&A

Insulating a Slab on Grade and Moisture Control

RochelleHansen | Posted in General Questions on

I recently purchased an older home (1977) slab on grade with no insulation or vapor barrier under the slab, in fact it was poured on loose shell rock. I found all the tack strips on the outside walls have been wet and are almost rotted and I can smell mildew on the carpet edges when I pulled it up to paint. I’ve done lots of reading and can’t find a solid answer so: how do I stop the moisture from coming in and insulate the floor under the carpet and the bottom around the outside?

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  1. paul_miltenburg | | #1

    It might be from condensation and not moisture intrusion. The carpet acts as a slight insulation layer keeping the slab cool enough to condense the humidity in the room.

    Do a search on here for insulating basement floors for ideas on how to stop this.

  2. GBA Editor
    Kiley Jacques | | #2

    There are a number of details here that you might want to consider for your situation: Building Plans for Energy Efficient Basement Remodeling.

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