I just recently gutted an upstairs apartment that was infested with squirrels. The rafters are 2×6 and are covered by the old lathe and plywood. The interior walls share the roof rafters and I am trying to get a reasonable R-value and still vent the rafters with rafter-mates…basically I have about 3.5″ for insulation. Someone suggested combining blown in urethane and fiberglass batt…what do you guys think?????
It’s getting cool!
Eman
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I have a similar situ. I ran 1x2's beside the rafters (flat for an airspace) then foil faced 1'' FG duct board (it was free) then 2'' of extruded foam board, and an 1 1/2 more foam board...then 1x3 strapping across the rafters filling in between with more 1'' duct board...then sheetrock.
totals are 4.3 R with the 1'' DB x2= 8.6
5.0 R with the EXT Foam x 3.5=17.5
total crammed R is 26.1 R in a 6.5'' thickness. Mebbe not the best, but the Duct board was free..find a supply house, they toss out the cut offs.
Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations.
I'm a fan of Urethane foam insulation. Just spray in 4" to 5" and you've got an R value of 24 to 30 , no venting required. Classifies as sandwich construction.