Attic walls, knee walls, and skylight shafts. What do these have in common?
1. They all all separate conditioned space from unconditioned space.
2. They all need to be insulated.
3. They are never insulated.
‘Never‘ is a strong word, and admittedly a word used in frustration based on my personal observations, but the point is these installations require more attention to detail than they normally receive.
Continuity is the key to control layers, so to ensure the continuity of the thermal control layer these borders between the conditioned space and the unconditioned attic space need to be addressed.
Considering the attic space can be both the hottest and coldest place in the house, it makes sense to deal with its thermal separation seriously. If we are claiming to build an envelope with any thermal integrity we need to do it properly, do our red pen test, and close the gaps.