What do I do to stop a cold breeze pouring through the light switch?

Dear Mark and Theresa,

I live in southern Vermont and winter just kicked in with a vengeance! It was 4 below zero when my 2 year old woke me up at 7:30 this morning, which was later than usual, so I was in good mood at the start of my day. My mood went south in a hurry as soon as I reached for the light switch in my family room. What I felt sent a chill up my spine (literally) – it was a strong cold breeze pouring through the light switch!!!

After further exploration, I discovered that nearly all of the switch plates and electrical outlets on the outside walls of my house have a similar breeze.

My knee-jerk reaction was to break out a can of spray insulation and have at it, but then filed that one under “bad idea”.

So what can I do, if anything? Thanks the help! Love the show!

Kevin from Vermont
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Kevin,

I would use low-expanding foam, sprayed in BEHIND and AROUND the box. Dow, the manufacturer of Great Stuff, says it can be used on contact with electrical boxes and wires (not inside the device itself—don’t fill inside the box).

Because you have 2×6 walls you probably have a 2-inch void BEHIND the box, so my electrician suggests sliding the nozzle of the can between the drywall and the box at the top of the box, then spraying until the void is filled.

The reason to use low-expanding foam is that you don’t want to deform the box or drywall with expanding foam, which is more suitable for other applications. And those other applications are available at this free download, which you can get here.

Let me know if this helps.