I have a 14'x28' shed that will be heated. I want to insulate the underside of the roof. There are no soffit vents, only gable vents. 2 questions: how should the venting be handled, and with 2x4 construction how can I get a higher r-value. r13 is standard for a 2x4 wall.

I have a 14'x28' shed that will be heated. I want to insulate the underside of the roof. There are no soffit vents, only gable vents. 2 questions: how should the venting be handled.

Since you only have cross ventilation you either install a ridge vent on the roof or use soffits vents but not all 3. only 2 of the 3 should be used



2x4 construction how can I get a higher r-value. r13 is standard for a 2x4 wall.

Hands down Spray foam is the best R per inch here. Its 3 times more expensive then Standard fiberglass but pays off quickly

Higher insulation value?

Polyisocyanurate board,R7 per inch.Finding it might pose a problem, here it's around an 8 hour round trip(for the factory seconds,which are more than 50% off new/firsts)

Installed between each rafter you can space them down by installing a 1X strip to each rafter,(against the roof line) to space them for venting, then using the soffit vents and ridge vents,you can have a heated room with proper venting.