Woodfiber
Woodfiber is an asphalt impregnated, rigid, woodfiber roof insulation made from virgin wood fiber and various secondary fibers. This manufacturing process provides superior qualities of moisture resistance and compressive strength.
Woodfiber is for use under loose laid, ballasted, fully adhered, and or mechanically fastened single-ply roof systems. It is also used in conventional B.U.R. and modified bitumen systems, or as a separation board in reroofing.
Woodfiber is available in 1/2" or 1" thickness and in 2x4, 4x4, and 4x8 size sheets *(note 1" is not available in the 4x8 size). The R-value for 1/2" is 1.39 and for 1" is 2.78.
Perlite
Perlite roof insulation is a homogenous board composed of expanded perlite particles, cellulose fibers and selected binders. Perlite is designed for use directly over steel decks and under built up roofing.
Perlite is available in both flat and tapered with thicknesses of 1/2", 3/4", and 1" with R-values of 1.39, 2.08, and 2.78.
The major manufacturers of perlite are GAF Corporation (GAFTemp, Permalite) and Johns Manville Corporation (Fesco). These manufacturers also produce cant and tapered edge.
Cant Strip
Cant strip is a rigid perlite insulation board cut at angles that provide a true 45 degree angle between horizontal and vertical surfaces.
Tapered Edge
Tapered edge can be made out of either perlite or woodfiber. Available in many sizes, tapered edge is used to move water to the scuppers or drains on the roof. Tapered edge may also used in an isocyanurate step down system to provide a smooth transition.
The following chart shows the different sizes and packaging available for tapered edge strips:
