This might be our shortest post ever. It’s a simple little tip to make you go DUH! It’s how to cut spray foam insulation.

BACK STORY: Recently while helping Emily at redo her bathroom for DIY network we spray-foamed her bathroom window gaps because when we removed the old trim her bathroom was suddenly like Ooook-lahoma, where the wind comes sweepin’ down the plain.

Anyone who uses this great stuff (see what I did there? If not, you’ve probably never used spray foam insulation) knows that you spray away, you don’t think you used that much, then you come back the next day and the area you sprayed looks something like this.


PRO TIP: Before you break the seal on that can of spray foam, walk around your house and find all the places you can spray this stuff. Once you break the seal you better use it all, because it’s basically a one-time use thing. There’s no saving it for later. It hardens up and you just wasted a whole can. I once heard Adam Carolla compare a can of Great Stuff Foam to a beer. Once you open that sucker you chug it. You don’t put the cap back on it and save it for later. 

I’ve tried lots of ways to cut away excess foam. The most succesful up to now was my Husky utility knife with a brand new blade. And that works ok for small amounts of foam, but once you get past the depth of the blade you start having to hack at the foam and dig at it and the next thing you know you’ve got shredded up foam.

Well here’s the tip.

First have a big breakfast meeting and have it catered by a bagel shop or someplace that will throw in a big old cheap, serrated bread knife.


Next, use that sucker to saw the foam. Hold it as flat to the wall as possible and it’ll saw through the cured foam like nothing.


And, that’s it. And yes, I could’ve probably written this post in one sentence. Or even just a tweet.

Is there a better way of cutting this foam that I’m missing?

Thanks for coming.

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