CertainTeed Flintlastic FR Cap 30 T Sheet is a fire rated, glass mat cap sheet used in two-ply or multi-layer modified bitumen fire rated roofing systems. It is designed for use as a cap sheet over inorganic and organic built-up roofing systems. It may also be used as a heavy-duty venting type base sheet when installed mineral side down and either mechanically fastened or spot mopped over lightweight insulating concrete decks or existing smooth surfaced membranes. Flintlastic FR Cap 30 T Sheet is reinforced with a tough fibrous glass fabric. It is surfaced with ceramic granules to provide a durable, heat reflective weathering surface when used as a cap sheet.