I recently had my windows changed. The workers spilled what I only know as "Builder's Foam" on my wall (and floor, but I fixed that). I have worked with this material myself and I know from experience that cleaning it off is an effing mess - unless you manage to clean it before it starts setting/puffing up.

Question: What is the best way to clean Builder's Foam[1] off semi-sensitive surfaces? (example: Painted walls, wallpaper, hardwood floors)

The workers in question seems to have solved it with mechanical/abrasion of the wall and then repainting. I cleaned the floor with careful application of a razorblade and light brushing.

[1] If Builders Foam is not understandable to everyone: It is a liquid-ish insulation/setting material that is often used to either insulate places you can't really reach or as a fast way to insulate around a window while at the same time providing structural support. It is blue, and it slowly "puffs up" after you apply it, setting in a foam-like rigid space-filling... foam. I don't know it's proper name, bonus points for identifying it...

1 Answer 1


It's called 'spray foam insulation'

Acetone (nail polish remover) will remove it - but it potentially will damage the surface that got contaminated.

On an unrelated note - you should demand that the window company pay you for damages/cleaning.

  • 1
    Minor clarification: acetone only works before the foam has set, and be aware that some nail polish removers don't contain acetone.
    – User95050
    Commented Jun 30, 2018 at 14:36

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