I recently discovered several areas in my home where cold air is infiltrating my home. The leak comes from under the wooden trim that runs along the floor on my exterior walls. I've pulled off the trim in these area found that there is a gap between the drywall and the concrete slab of my patio home. Can I simply fill this gap with spray from from the inside of my home or is there another method that I should take?

Thanks for your help!

How large is the gap? If you were to use the spray type foam, you have to be careful not to use too much because this product expands and may cause greater problems. My suggestion would be to use a silicon/latex caulk for exterior use.

Foam-in-a-can works fine if you know how. DAP makes one that is pretty easy to use. The polyisocyanurate ones can be real interesting. Especially if you don't READ AND FOLLOW THE INSTRUCTIONS. You will be replacing floor coverings, furniture, drapes, whatever, if you don't follow instructions. Plain old caulk works well, it just doesn't expand and insulate. I like DAP Dynaflex 230 for important sealing jobs.

Thanks, I will try the DAP. I assume I should wait until spring when temperatures are above 32F ?

Thanks, I will try the DAP. I assume I should wait until spring when temperatures are above 32F ?

Yes, do it when it is warmer. Everything will work better then, both the caulk and you. Jamb something in the crack for now. A putty knife and long narrow strip of cloth would work. It also would be easy to remove later.

EPM