1.Cap sheet: the finish bitumen granule cap sheet. granules add fire resistance, colour options and UV protection. The torch is used heat the bottom of the cap to the top of the base sheet. When the two layers are pressed together, they form a seal.
2.Base sheet: this is the first layer of modified bitumen membrane torched down.
3.Overlay board: supports the roofing membrane.
4.vapour barrier: prevent condensation and moisture.
5.Insulation: applied first, attached with screw and plates. retains heat in the structure.