Xtratherm TR/BGM is a high performance Polyisocyanurate tapered roof insulation with a polypropylene fleece finished bitumen/glass fibre working surface and a mineral glass facing to the under side. (TR/BGM boards are not reversible) TR/BGM is suitable for use below most bitumen based partially bonded built up roofing systems. TR/BGM is part of Xtratherm’s comprehensive range of high performance tapered roof boards providing total solutions for tapered roof projects.