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Air-sealing in frigid weather. Can foam or caulk?

agurkas | Posted in Energy Efficiency and Durability on

My house is bone dry (humidity in the teens). I know most of my walls are empty and likely I will not be blowing in dense pack cellulose until spring. So I have a house with air coming in at baseboards on the 1st floor. See IR camera picture attached.

I also have could areas around doors where I removed the trim and I can see outside trim through the gaps.

Here is the problem: it is 10F to 20F in Boston right now. I know Great Stuff canned spray foam needs temperature and moisture to cure. I can mist whee I need to seal, but not sure if I can use it from inside when likely door frames are like 20 degrees at best.

I could do caulk, but filling 1/2 gap around door – not sure how effective it is with caulk.


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  1. Dana1 | | #1

    Caulk would be fine up to 1/2:". If you have sections where the gaps are too wide and it doesn't seem to work, you can heat up the surface with a hair drier to where it's warm to the touch, then quickly wet it with water with an atomizer just before hitting it with can-foam. The water helps it rise & cure faster, so even if it cools quickly it'll still seal & stick.

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