Rigid multi-layer plaster cement mortar waterproof layer should be used not less than the original ordinary Portland cement and expansion of cement, slag Portland cement can also be used; sand using particle size 1 ~ 3 mm coarse sand, requiring sand Hard, rough, clean; cement slurry and cement mortar with the ratio should be based on water requirements, raw material composite railing cost per foot performance and construction methods to determine the construction must be strictly controlled. At present, some buildings also have flexible waterproof layer, the roof garden often "three felt four oil" or "two felt three oil", combined with PVC cement or polyvinyl chloride coating treatment.

In recent years, some new waterproof materials have begun to put into use, has been put into the roof of the construction of EPDM coil, the use of good results. Abroad also try to use the hollow class of foam products as green soil and roof between the good drainage layer and filler teak wood plastic polish to reduce the weight. Useful renewable rubber backing, coupled with asphalt waterproof coating, paste thick 3 mm glass fiber cloth as a waterproof layer, which is more conducive to rapid construction.

There is also between the waterproof layer and the slate to set the insulator layer (as a buffer zone), to prevent upward transmission of vibration, and waterproof, heat, but also in the green roof of the floor to do PUK polyurethane coating waterproof layer, to prevent leakage The Roof waterproof layer regardless of which form and materials, constitute the entire decking material outdoor environment roof of the waterproof drainage system, all the necessary pipes, flues, drainage holes, embedded iron and pillars and other roof out of the facilities, should be done in the roof waterproof Layer to properly handle the node structure, with particular attention to the connection with the soil part.