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Community and Q&A

Spray foam – can I spray a second layer of foam over the first layer? If so, any preparation required?

ccnr | Posted in Energy Efficiency and Durability on

Home owner wants twice the foam thickness – currently has 0.5 inches on underside of flooring, & wants to double this.

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  1. GBA Editor
    Martin Holladay | | #1

    Are you a professional spray foam contractor? Have you been trained or certified in any way?

  2. ccnr | | #2

    I'm the homeowner.... my contractor's helpers under sprayed - it was supposed to be R-7, but their depth was only 0.3-0.5 inches for closed cell foam. It should be 1-1.5 inches, right? The product is Lapolla, I think that's how they spelled it. They're coming back to re-spray. Just want another opinion that over-layering is as simple as applying another coat with no preparation.

    I'm uncertain of their guidance because after they assured me the current fiberglass insulation should be removed prior to spraying, they sprayed over the fiberglass insulation their helper failed to remove. They've assured me they will correct that prior to re-spraying.

  3. GBA Editor
    Martin Holladay | | #3

    Yes, it's possible (and common) to increase the thickness of spray foam by spraying a second layer of foam on top of a layer of cured foam. And if your contract calls for R-7, that's what the spray foam contractor should deliver -- so the second application should not incur any additional cost to you.

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