Now the material itself will be discussed. The most common types are boards. They are made of different types of materials. Rigid board insulation can be tapered. As mentioned before, tapering makes insulation sloped so it creates drainage.
Some boards have a special surface called a facer.
There are many types of insulation. Three common types of rigid board insulation are perlite, wood fiber and polyisocyanurate foam. Perlite roof insulation boards are made of a volcanic ore. This ore is combined with organic fibers and binders. Wood fiber insulation looks a lot like perlite.