The main function of the metal roof of the double-layer tile machine is to shield the building from wind and rain. According to its performance and characteristics, the metal roof can be divided into rainproof and sexual roof.

Water-shedding roofing slabs are evolved from the development of the early classical metal roofing system. Such roofing slabs are not large in size, regular in shape, no ribs or ribs are not high, and between the slabs. Overlapping and crimping each other, such as flat buckle overlapping plates, the connection between the plates is generally not sealed. The roof is mainly drained by the gravity of rainwater, and the connection between the plates is by structural measures. Rainproof roof panels are similar to botu roofs. Generally, this kind of roof needs to be designed with a larger drainage slope. The larger the roof slope, the faster the drainage of rainwater. Support and cushions should be provided at the lower part of the roof during use.