We have an enclosed building that has been spray foamed years ago. By now it's very dark and dirty in the building and we found out we can brush it down with the broom. It works well and changes it back to original color but it just creates a lot of dust. How dangerous is this dust, or is there some better way to do it?

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    If you don't know what the foam is (and I assume you don't because you didn't tell us), how would we?
    – isherwood
    May 11, 2021 at 12:46
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    You might consider covering the foam to protect it. Anything from drywall or plywood/OSB to simply painting it. Of course, if you choose to paint it, make sure you identify the foam so you can use a paint that won't damage it.
    – FreeMan
    May 11, 2021 at 13:04
  • Exposed spray foam is a fire hazard (virtually all common types of it), so covering it with an easily cleanable (and white, since light is desired) surface would be a good idea. Aside from those already mentioned, pre-painted steel sheets are common in utility/farm buildings.
    – Ecnerwal
    May 11, 2021 at 14:04
  • How can we possibly know the toxicity of your local dust? Bakery... Lead mine... Chernobyl unit 4... Different answer in each case, obviously... May 11, 2021 at 18:03
  • Why not add a picture of the spray foam? Many types are very durable.
    – K H
    May 12, 2021 at 3:16

1 Answer 1


The dust by itself isn't dangerous since the foam's not breaking up but large quantities of regular dirt and dust are not good to breath under any circumstance. You would be better off getting a good shop vac and vacuuming the foam with the attachment brush. If you could get one with a long hose so the pump wouldn't be exhausting into the same room it would be better. You should also wear a mask to keep from inhaling the dust.

  • Yes i don't know what kind of foam it is ... it's the yellow older stuff but it does actually seem like some foam brushes off and gets into the air... thanks for those ideas already has helped May 11, 2021 at 13:50

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