I have a question regarding adding more insulation above my attic floor.
I have steel liner panels for ceiling in my pole barn, with poly vapor barrier under the steel stapled to the trusses.
In the center of the trusses, I have OSB flooring (spread web trusses allowing for 7' head clearance). This OSB floor section is 10' wide and runs the length of the building perpendicular to the trusses.
On either side of the OSB, I have 17.5 inches of blown in fiberglass for R49 insulation. Due to the flooring above the bottom cord of the trusses, before the liner panels were installed, R19 bats were stapled to the trusses from below.
I would like to add foam board (2 layers of 2 inch) and then another layer of OSB on top of the existing OSB in order to increase the R value in this area closer to the R49 I have in the rest.
My question is regarding vapor barrier. Since I have vapor barrier facing the conditioned side (between liner panels and R19 bats), will I get moisture issues considering the foam board provides another vapor barrier at the top?
Sketches below in case they are clearer than my description.
I have steel liner panels for ceiling in my pole barn, with poly vapor barrier under the steel stapled to the trusses.
In the center of the trusses, I have OSB flooring (spread web trusses allowing for 7' head clearance). This OSB floor section is 10' wide and runs the length of the building perpendicular to the trusses.
On either side of the OSB, I have 17.5 inches of blown in fiberglass for R49 insulation. Due to the flooring above the bottom cord of the trusses, before the liner panels were installed, R19 bats were stapled to the trusses from below.
I would like to add foam board (2 layers of 2 inch) and then another layer of OSB on top of the existing OSB in order to increase the R value in this area closer to the R49 I have in the rest.
My question is regarding vapor barrier. Since I have vapor barrier facing the conditioned side (between liner panels and R19 bats), will I get moisture issues considering the foam board provides another vapor barrier at the top?
Sketches below in case they are clearer than my description.
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