I am currently framing the exterior basement walls of a house with the end goal of adding insulation and vapour barrier to the framing. The foundation wall is poured-concrete. It is not likely to have leaking issues since the outside was recently waterproofed.
The basement walls perpendicular to the floor joists look like this:
I’m pretty confident in my plan of attack for these walls. Build a framed wall 2” from the concrete wall (already done), insulate framed wall with fibreglass batts, seal with vapour barrier: then, insulate the headers the same way.
It gets a little more complicated when you look at my walls that are parallel to the floor joists:
Here, I plan to again build the framed wall ~2” from the concrete wall, by adding blocking which will allow me to fasten the top plate.
But what I’m puzzled about is: how to insulate the big void where the “header” would be, above the framed wall?
The concrete wall goes almost all the way up to the subfloor, with a small 2” gap, as shown in the photo (notice the gap where the pex piping goes):
To sum up my question:
- What’s the correct way to insulate the “header” above the framed wall in the last 2 photos? (If it’s even needed?)
- In the 3rd photo, need I also add some kind of insulation (spray foam?) to the narrow gap above the foundation wall? Or would I just be wasting my time?
