Knee attic insulation in old construction
I really appreciate everyone’s input on other thread. I wanted to delve into knee attic insulation because the two consultants I’m working with agreed on everything else but disagreed on this.
First option: spray foam (open cell) on underside of roof (which happens to be slate with wood backing so the foam would not touch slate).
Second option: insulate wall and floor of each knee attic using inexpensive rolls with hard foam backing for air sealing.
In both cases the third floor living space will be fully within the “envelope”.
What are the considerations for choosing one option over the other and what questions should I ask?
GBA Detail Library
A collection of one thousand construction details organized by climate and house part