Installing Three Types of Basement Insulation
Hi – I live in zone 4 and am finishing my basement. It is a poured concrete foundation house built in 2006. I have purchased the DAP Touch n’ Faom 2 component foam pro system to seal the rim joists with 2 inches of closed-cell foam then replace the fiberglass batts that were originally there. Next I was planning to adhere 1-2 inches of foamboard insulation to the concrete walls (R5-R10) then frame in front of that with 2×4 and fireblock with 3/4 inch plywood. I have a couple of questions:
1- Due to the large sewage pipe there are areas I won’t be able to get foamboard insulation on the walls (behind the pipes). Any thoughts on how to address this?
2 – Should I put fiberglass batts in the stud bays? Should these be faced or unfaced if necessary?
3 – When using the spray foam I plan to wear proper PPE and keep the egress window open but do I have to have my family leave the upstairs during the process and if so for how long?
Thanks for your help.
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
For CZ4, you're required to install R10ci or R13. Installing 2" R10 tapped rigid foam is good by itself, but you can do a minimum R5+R13 in a 2x4 wall as well. You could install 2-1" taped rigid foam with staggered seams for higher protection.
The batt insulation can be either, but you need to make sure the rigid foam is sealed on all joints, seams and cracks, and encapsulate and seal all penetrations and pipes with sprayed foam before you install any batt insulation.
As far as IAQ safety, 24hr open clearance should be enough. Make sure you read up on the manufacturers installation and safety information.
Thanks Armando. I’ll plan to just use 2 inch foam board to get R10 if that’s all I need. Got the wall that has the large sewage pipe that I can’t get foam board behind you feel I can just use foam insulation around it. Just in the gaps between the pipe and foam board or do I need to cover the whole pipe?
If it was me, I would encapsulate all pipes, that way I'll make sure there are no gaps or cracks.
Hi Armando. One more question. If the studs are not pressed up to the foam board due to various obstruction (there could be 2-4 inches of space) do I need to insulate the stud cavities or is foam board still considered continuous? Mike