Under the roof above the stairwell—aren’t you glad you didn’t have to figure this mess out. NB: the lumber is straight despite curving effects from the lens.
We’re thinking about going with Icynene®* foam insulation between the joists up against the roof or exterior walls, which seals the heat out of all interior spaces.
Icynene® insulation and air barrier system creates an airtight seal to reduce random air leakage through the walls and limit the penetration of outdoor allergens and pollutants. 100% water-blown, Icynene improves the quality of the indoor air you breathe. It also reduces the number of indoor pollutants to help you breathe easier and is an environmentally-friendly soft foam insulation.
Anybody had any experience with this stuff? Watch the videos to see the foam expand!
* From the product spec sheet: “Icynene® spray formula is a 1/2 lb density free rise, open celled material.” FYI