FELT ROOFING, REINFORCED BITUMEN MEMBRANES (RBM)
What is it? Built-up RBM are the most common material for residential flat roofs, as well as for major roofing contracts and there has been a lot of product development in recent years. Three layers of sheet materials are rolled out over the roof and bonded together with hot bitumen. These sheet materials are based on a carrier normally polyester of varying strengths and coated in bitumen so that they fuse together to form a single waterproof layer. The membrane is laid onto insulation when applied over a heated building or part of a building with the insulation bonded to a vapour control layer which in turn is attached to the roof deck. This build up is known as the warm roof and is very successful.