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Soft closed cell foam. What’s the problem?

newmedia | Posted in General Questions on

Hello all, 

Let’s say your closed cell foam is soft. (I mean it’s really soft. You can punch a hole with your finger. ) Is is Part B heavy foam?

Thank you,

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  1. Expert Member
    BILL WICHERS | | #1

    Closed cell spray foam isn’t soft — it’s pretty solid. You can actually snap a piece of it with a pretty clean break for thin chunks, and for larger pieces it’s essentially structural and quite strong.

    If you can poke your finger through the foam, it’s probably not closed cell spray foam. Open cell spray foam is much softer, but even open cell is usually tougher than you describe so you might have some unusual type of foam or some kind of application issue.

    I’m not sure what you mean by “is part B heavy foam”. The two components to spray foam are a resin and a curing agent, basically. You don’t get any foam at all unless you mix the two together in the correct proportions. If you’re thinking something like “maybe they only applied part A so my foam is soft”, it doesn’t work that way. If only one of the two materials was applied, you’d have a gooey mess and no foam at all.


    1. newmedia | | #3

      Thank you Bill. There was open cell SPF on top of closed cell SPF for the roof insulation.
      I got confused a bit, since I don't know that's how the roof insulation is done.
      I though some part is soft, but it's not.

  2. Expert Member
    Michael Maines | | #2

    Jin, the problem could be with the ratios of the A-side and B-side components. Another likely issue is installation in lifts that are too thick so exothermic reaction gets too hot. Or possibly they used a 1.5lb mix, which some companies call closed cell, instead of the more typical 2.0 lb mix. Or they used open-cell foam. How consistent is the problem?

    1. newmedia | | #4

      It's closed cell SPF. I cut it with my knife and tested it. It seems it's strong.
      As I replied in the Bill's comment, I got confused a bit. Thank you so much for your answer!

  3. MattJF | | #5

    Do you have the name of the product they used? Most suppliers will send a rep out to inspect your foam if a defect is suspected. Or they will check out samples in the lab.

    How did you test it to confirm closed cell?

  4. newmedia | | #6

    I spoke with the installer. He explained what's there. I don't see any significant problem.

    The reason why I was asking about it was I didn't expect to find the closed cell there. I'm just normal home owner. :)

    Generally, soft smelly closed cell SPF tells you that something went wrong. (Heavy Part B).

  5. MattJF | | #7

    Were you expecting open or closed cell?

    There are a tons of things that can go wrong with SPF, off ratio (heavy part B or A) is only one way of many to screw it up.

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