insulation product generically called stress skin panels. Plug this phrase into any search engine and you’ll find suppliers. Stress skin panels are factory-made insulating sandwiches of plywood or waferboard bonded to a 4, 6 or 8-inch thick layer of rigid foam. Order the panels to fit your roof, then hoist them up top and fasten them to rafters with long, 1/4-inch diameter bolts.

Another approach is to simulate the stress skin panel with site-assembled sheet goods and rigid foam. Layer at least 4 inches of extruded polystyrene foam on to the roof deck, then top it off with a layer of 1/2-inch plywood. The biggest challenge with either of these approaches is finishing the thickened eaves area. But that’s nothing compared to the hassle of covering an interior ceiling with insulation.