Cut and Cobble
I’m doing cut and cobble on my attic with 2 inch polyiso and the temperature inside the attic have dropped by 20-30 degrees from before but nowhere near expected.
On a hot day, its about 104F outside and it can be 102-104F inside the attic, and 88-90 inside the house. I was expecting on this kind of days, 85-88F inside the attic. My zone is 3B and the code calls for R5, but I have R13 (2 inch polyiso) underneath roof sheathings.
What was the issue? Some missed spot? Not thick enough? When I install HVAC unit next, will there be a problem under these condition? (planning to run all metal duct without duct insulation).
GBA Detail Library
A collection of one thousand construction details organized by climate and house part