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moisture barrier for slab foundation in CZ 2

merlinm | Posted in General Questions on

Concrete slab foundation in CZ 2 getting ready to be poured. Finished floor will be polished concrete.  Slab consists of a grid of deep grade beams with a 6″ slab. The beams and slab will be one monolithic pour. 

Opinions sought on whether the moisture barrier should be continuous or whether the bottom of the grade beams should be left open. 


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  1. Expert Member
    PETER G ENGLE PE | | #1

    The moisture barrier must be continuous. This is not fun with grade beams, but still very important. Buy lots of tape that is compatible with your moisture barrier. You'll need it.

  2. merlinm | | #2

    Thanks, Peter. The structural engineer who designed the foundation says the bleed water at the bottom of the beam needs somewhere to go. Some of the grade beams are 6 to 8' deep. Soil is limestone rock.

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