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Density of polyiso compared to XPS?

whitenack | Posted in Green Products and Materials on

A local supply house is running a good discount on Polyiso. My builder is familiar with XPS, but not polyiso, and is asking me about the density. How does it compare?

I think the trouble is that he has been bitten by crumbly EPS in the past and doesn’t want to go down that road again.

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Replies

  1. GBA Editor
    Martin Holladay | | #1

    Clay,
    The density of polyiso typically ranges from 2.0 to 2.5 pounds per cubic foot.

    The density of XPS ranges from 1.5 to 2.8 pounds per cubic foot.

  2. Dana1 | | #2

    Roofing iso is typically ~2-2.5lbs, density with a higher pounds per square inch resistance to make it "walkable" when covered by a membrane roof. I think there are a few lower density lower psi wall sheathing products out there, but can't point you to a specification without some web-searching.

    Polyiso (at any density) doesn't have the macroscopic bead structure that makes low-density EPS so fragile. The facers add some ruggedness against denting, but are primarily there to lower the vapor permeance.

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