IKO Type 6 Glass Ply Sheet Asphalt Saturated Fiberglass Mat is composed of a high-strength inorganic, non-woven fiberglass mat, which has been thoroughly permeated with premium asphalt. Offering greater moisture resistance than a conventional four-ply organic felt built-up roofing system, this sheet’s surface is sanded to prevent sticking in the roll. IKO Type 6 Glass Ply Sheet also offers superior “breaking strength” characteristics in both longitudinal and transverse directions, thereby enabling a four-ply application to provide even greater performance characteristics.