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Slab on grade polyethylene placed below or above foam board insulation

Bob Holodinsky | Posted in General Questions on

Is there any issue placing the plastic sheeting under the foam board insulation to protect it from punctures caused by rebar placement and tears during the pour?

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  1. GBA Editor
    Martin Holladay | | #1

    Above the foam is better. Otherwise the poly can hold water from rain (if it rains before the concrete can be placed) or from bleed water that comes from the concrete. The water will keep the concrete damp for a long time, and may delay installation of the finish flooring.

  2. Bob Holodinsky | | #2

    Thank you ...I will have to stress the importance of not compromising the plastic sheeting when preparing for the pour...regards,Bob

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