My $9 can of spray foam turned my drafty back door into a sealed one in about an hour last Saturday

Sean Perry · 2026-09-24T09:15:05.218218+00:00

For two winters I just dealt with the cold air rolling in under my back door in Grand Rapids. My furnace ran nonstop and my last gas bill was $186, which felt insane for a 900 square foot house. I finally crouched down with a flashlight two Saturdays ago and saw daylight all along the bottom edge where the door meets the threshold. I thought I needed a whole new door, but a guy at the hardware store on Division pointed me to a $9 can of spray foam and a $4 tube of silicone. I spent about an hour taping off the sides, filling the gap under the threshold from the outside, and smoothing it with a putty knife once it set up. This month's gas bill came in at $141, and the floor by that door is no longer freezing when I walk past it in socks. Has anyone else sealed a gap like this and had good luck with it holding up through a wet spring, or do I need to worry about the foam cracking?

🐿️Pinecone Attack

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My $9 can of spray foam turned my drafty back door into a sealed one in about an hour last Saturday | Broke But Brilliant - Pinecone Attack