Insulation has been installed on my bedroom ceiling with the white foam side showing and the shiny side against the ceiling. Does the exposed foam side pose any dangers?

  • 1
    What sort of dangers are you thinking about? Any foam panel (no matter which way the facing is pointing) can emit toxic fumes as it burns.
    – FreeMan
    Feb 24, 2023 at 12:41
  • I'm not aware that any of the commonly used foam boards (XPS, EPS, Polyisocyanurate) have a covering on only one side. Those seem to have no covering at all (XPS, EPS) or something on both sides (Polyiso...).
    – SteveSh
    Feb 24, 2023 at 12:45
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    Is the foam going to be covered with something? Wall board, Wood? Can you please give us more details as to the situation.
    – RMDman
    Feb 24, 2023 at 12:52
  • Does this answer your question? Are there any dangers associated with rigid foam insulation?
    – isherwood
    Feb 24, 2023 at 13:46

1 Answer 1


The foam just sitting there is not a problem normally. Any residual chemicals from manufacturing will dissipate fairly quickly and the foam itself is quite stable.

The problem is fire. Many foams both burn easily and emit toxic fumes when they burn. Almost anything that burns will be toxic if you breathe in too much carbon dioxide and not enough oxygen, but foam can be extremely dangerous.

The usual solution is to have a fire barrier between you and the foam. Typical in the US is drywall. Drywall is basically ground up stone (gypsum) between layers of paper. It is quite good at slowing down a fire. And even wood can do fairly well - we think of putting wood in a fireplace but it doesn't actually catch fire all that fast. Bare foam? Doesn't matter shiny side or not, it is considered quite dangerous in a house fire.

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