Spray foam is relatively easy to install; doesn't always require removing your old roof system, and once it's in place, it has one of the best insulating qualities of any roof system. It can be used on both new roofs and reroofs. In many circumstances, the foam can be sprayed directly onto the existing roof during retrofit or re-roof operations. Spray foam is often the best option for roofs needing additional insulation value without needing a full tearoff.