Warning: that insulation foam spray contains a hidden danger

I was cleaning out my garage attic and found a can of Great Stuff foam from years ago. I read the label closer and it says the propellant is flammable even after it dries if you cut into it deep enough to expose fresh foam. Nearly set my garage on fire with a saw blade trying to trim some old stuff. Has anyone else run into this or know if there's a safer way to remove cured foam?

2 comments

2 Comments

oliverbailey8d ago

I heard a contractor say spraying water on the foam before cutting it helps reduce the spark risk.

jamiegreen8d ago

Wait, you mean like a damp spray bottle or just hosing it down? @oliverbailey, I've tried wetting the foam a bit before cutting with a hot knife, and it did help keep the dust down and seemed to stop any stray sparks from the cheap tool I was using. I just gave it a light mist, nothing crazy, and made sure the area was dry enough to work without slipping. It's not a foolproof fix, but for a quick job on some closed-cell foam, it worked better than going in bone dry.