If I use polyiso foam board insulation in my sauna and completely cover it with aluminum vapor barrier / tape, creating a seal, will it outgas dangerous CFCs into my sauna at high temperatures?

What about covering the face of the foam board insulation with rockwool? Would that help?

  • Foam insulation boards are made under very controlled conditions. The material should be fully reacted and inert. Have you read somewhere that they can release CFCs at sauna temperatures? If so, is it in harmful quantities and continuous over the life of the insulation or is it just an initial phenomenon? If it is actually a potential problem that you need a long-term solution for, you would need something that creates a gas-tight seal. Rockwool wouldn't do anything. But in that case, the foam board might just be an inappropriate insulation, and you should just use a different material.
    – fixer1234
    Sep 25, 2018 at 0:59
  • Rockwool would just be to provide insulation to the foamboard itself. Do you think foam board is safe at ~100C temperatures. i want to use polyiso because it is the best insulation and i need to keep adjacent rooms from heating. other thoughts? thanks Sep 25, 2018 at 2:47


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