Insulation boards are rigid boards or sheets made of foamed polystyrene, polyurethane, polyisocyanurate, or gypsum. Their rigid, closed-cell structures provide better insulation compared to ...

Insulation types with higher R-values offer ... Use fiberglass batts cut to fit snugly between studs. Add rigid foam boards on the backside of the wall to boost R-value and prevent air leaks.