I just built a pole building. One 12 X 32 section is going to be my wood shop. The roof is constructed of 2 X 8 rafters with charcoal grey asphalt shingles on top of the 1/2" plywood sheathing and felt.
I stapled dual-sided radiant foil barrier to the under side of the rafters. Have a continuous soffit vent and ridge vent. No other insulation in roof.
The walls, so far, are just the exterior 5/8" T1-11 sheathing. I will eventually insulate the walls with conventional fiberglass batts.
Immediately after putting up the RFB, the temp dropped from 90 deg in the shop to 80 deg. This was on a sunny day with outside temps in the mid-to-high 90s.
I'm hoping that this will work in "reverse" during the winter and that the RFB will reflect the heat from my heater back down into the shop.