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Community and Q&A

Basement Insulation

AldoLeopold42 | Posted in General Questions on

I am going to be insulating my basement with rigid foam and I notice that Foamular has been reformulated to be more environmentally friendly (as much as XPS can be). Would the new Foamular NGX 250 or 150 be ok to use for my basement walls? If so, would 250 or 150 be better?

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  1. Expert Member
    BILL WICHERS | | #1

    I don't see any reason the new Foamular would be a problem. My understanding is the only difference is that they are using more enviornmentally benign blowing agents for the new product.

    You only need the 150 version for basement wall insulation. The difference between the two is the compressive strength of the material -- the 150 version is good for 15 PSI, the 250 version is good for 25 PSI. This can be important for underslab applications where the XPS material will be supporting a load on top, but in a wall that doesn't really matter so you can use the cheaper version with the lower rating. Aside from that, the two types are interchangeable.


  2. AldoLeopold42 | | #2

    Thanks Bill…appreciate the help! I will go with the 2” Foamular 150 NGX.

  3. Expert Member
    Michael Maines | | #3

    Toley, Foamular 150 NGX will function just fine, as long as you cover it with an approved fire barrier, typically 1/2" drywall. It is slightly better than conventional XPS, with roughly 75% the impact. Still much worse than alternatives such as polyiso, which, if you choose Thermax brand, can be left exposed.

    1. AldoLeopold42 | | #4

      Thanks Michael…do you mean drywall over the xps when insulating the rim joists? I plan on installing plywood on top of the top plate, extending back to the sill for my wall fireblocking.

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