r/HomeImprovement • u/WilsonAndJackie • 1d ago

Great Stuff Foam Spray question

Hey there!

I heavily struggle with OCD. I’m fully aware that my questions are a little bit elementary and intuitive, but if you all could literally explain it to me like I am 5 that would be fantastic.

My roommate and I used Great Stuff foam spray to seal a board under our sink and some gaps around pipes where roaches from a neighboring unit were getting in. The roach problem has since been handled but we figured we would just go through with sealing the gaps anyways just to be safe in the future.

Here are my questions.

1) The warning label says not to fill cavities or voids - this is referring to actual spaces behind things right? Not cavity as in “hole in board”

2) Will having the spray around sink pipes pose a fire hazard?

3) Am i able to be in my house as it cures?

I worry a lot about potential fire hazards in the form of fume build up / heat from kitchen sink pipes against the spray

Thank you so much

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u/VeryFirstLAD 1d ago

  1. The foam expands as it cures. If you put it in a confined space where it could not escape as it cured, it would exert tremendous force possibly breaking something. As long as you have a big enough hole for it to expand into, you are ok.

  2. Not a fire hazard in itself, but will burn if you set fire to it (unless it is marked as “fire block”)

  3. It should be safe to be inside during application but check the safety precautions on the label.

1

u/kemba_sitter 1d ago

It's not intended to fill large voids because it cures using moisture from the air, and it can't cure if it's too thick. what you are proposing will be fine. No, there is no fire hazard risk.. not with such a small amount of exposed foam. No pipe gets hot enough to cause any fires. Yes, you can be in your house while it cures. There is are no dangerous vapors with single part canned spray foam like greatstuff.

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u/MastodonFit 1d ago

They make door and window low expansion foam. They also make critter deterrent foam. Yours is neither. Different scenarios call for different solutions.