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Underslab insulation: Thermofoam

canadianexpy | Posted in General Questions on


I looking for underslab insulation for my house, was hoping to find used but can’t find any.
This product Thermofoam has come up at a reasonable price for new.
I was just going to use the 2″ as I am not heating the floors.
Anyone see any issues with this insulation?
Specifications  attached.
Could this also be used under a garage slab?
Thanks for any input.

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  1. GBA Editor
    Martin Holladay | | #1

    The brand of rigid foam you're talking about (Thermofoam) is expanded polystyrene, also known as EPS. You can certainly use this type of rigid foam under a slab, as the brochure from the manufacturer indicates.

    For more information, see this article: "Choosing Rigid Foam."

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