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Community and Q&A

Slab on grade and plumbing penetrations

John Rockwell | Posted in Green Building Techniques on

I am looking for specific information about detailing plumbing waste lines for a slab on grade on Cape Ann (north of Boston, Zone 5A). I am concerned about sub-slab insulation, the air barrier, vapor barrier and general coordination of excavation, concrete and plumbing trades. I am familiar with Building Science Corporation’s recommendations for polyethylene location and “no fines” in the stone layer.

Thank you,
John Rockwell
Rockport, MA

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  1. David Meiland | | #1

    Prior to the pour, tape the pipe penetrations to the plastic sheet, then put a piece of pipe insulation around each pipe that sticks up flush with top of slab. Later, if you want to, you can trim the pipe insulation below the slab a bit and replace with canned foam. There are a few useful details shown near the end of this document

  2. Jesse Thompson | | #2

    The 100K House folks used to have a very good page on using Stego wrap and how to seal penetrations, luckily the Google cache is still visible:

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