Built-up systems are constructed though alternating layers of reinforcing fabrics and an adhesive bitumen to produce a membrane. Adhesives are applied either hot or cold depending on type, and surfacing aggregates like gravel can be used. The bottom-most layer is sometimes mechanically fastened, and built-up roofs are referred to as fully-adhered only when they are attached directly to the building's insulation or roof deck.
Buy built-up system roofing services
Or contact the seller
in section "Installation of roof"