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Underlayment for flooring needed for open crawlspace cabin ?

tristan123 | Posted in Energy Efficiency and Durability on

Hi everyone,

I am building a small cabin with an open crawlspace (cabin is supported by 6×6 posts, 6 ft to 2 ft off the ground as terrain is sloped), the floor assembly will look like (going from exterior to interior), PT OSB boards, 3/4 in foam board taped together, hardware cloth, 2×10 wood joists with R30 fiberglass insulation with paper towards the bottom of the subfloor, 3/4 in OSB subfloor glued to floor joist and glue in the tongue and grooves between sheets then LVP flooring on top of that.

Would there be any value in having an underlayment under the LVP floating planks (moisture protection of the LVP planks?) or could this potentially create more problems by trapping moisture in the floor assembly ?

Thank you for your help !

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  1. Expert Member
    Michael Maines | | #1

    This is a good overview article: I don't see a need for a vapor retarder under your flooring.

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