Insulating an Attic With Knee Wall
Looking for the best way to insulate an attic area with a knee wall above a flat soffit ceiling area in a kitchen remodel (60 year old stucco and wood frame) in Zone 3C marine climate (no snow/ice/little rain/mild temps year round)
The twist (maybe) is that both sides of the knee wall do still connect to shallow attic area due to low slope roof to both sides of the gable – and they in turn still connect somewhat to the rest of the larger attic for the house. I would say that as far a cross ventilation this area in the diagram is still 90% on its own.
The kitchen is down to studs and rafters except the cathedral ceiling area (which creates the knee wall) is complete with rigid polyiso foam installed with a 2.5 inch air gap that leads up to ridge vent. Drywall is not yet installed over this polyiso and i will likely will add 2 inch rockwool to the cathedral section before drywall.
So basically the question is mostly about different treatments involving batts/foam/membranes/facings on this knee wall….
Please see the diagrams attached…
What is best insulation treatment for a gable wall with shallow sloped attic adjacent to both sides at :
(A) interior knee wall and
(B) soffit ceiling
(C) and possibly the exterior gable wall
Thanks in advance
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