Building roof as bearing and building external envelope structure at the top of the enclosure, it is very important to the entire facade and building, is an important part of the light steel structure bracing system most prone to the Water Leakage. Its main role is to resist the wind, rain, snow and the sun's radiation, and bear the weight of the roof and the roof of the wind, snow and the load on the [1]. Light steel roof structure according to the materials used are color steel plate, color steel sandwich panels, shingles, a variety of colorful light roof panel, GRC board, arched corrugated metal roof, composite steel plate and other types of [2], light steel structure roof and wall materials mainly used color pressure plate or sandwich plate. Color pressure plate link has 3600 edge plate, dark buckle lap connection, also hit the nail plate. For type C or Z thin wall purlin type steel purlin has light weight, roof slope design is generally 1/10 ~ 1/15.
There are two kinds of steel structure system, the roof and the roof, which have long connection and lateral connection. The connection is mainly to long lap, namely uphill downhill ski plate, set up special waterproof sealant joint with special fixed layering, lateral connection mode and at present there are three main types: 2.1 lap joints; 2.2 button type connection; 2.3 occlusion type connection button;