FlintBoard® ISO-T Tapered Polyisocyanurate Roof Insulation is manufactured in a tapered profile to offer the combination of high thermal value plus promotion of proper roof drainage. FlintBoard ISO-T tapered polyiso roof insulation is specifically recommended for hot asphalt, coal tar BUR, modified bitumen and single-ply membrane roofing systems. FlintBoard ISO-T is offered in a variety of thicknesses, providing long-term thermal resistance (LTTR) values from 4.2 to 12.9. Higher LTTR values can be achieved with layers of flat FlintBoard ISO. FlintBoard ISO-T is a closed-cell, polyiso core integrally laminated to heavy, black (non-asphaltic), fiber-reinforced felt facers. FlintBoard ISO-T is also available in 25-psi formula.