Steel frame roofing method: The civil construction does not make a tic-shaped beam structure, but only leaves a rectangular, square or circular opening. According to the size of the opening and design requirements,  there are generally two methods:

2. Grid structure: This method is suitable for situations where the reserved openings are large and the general light steel structure cannot meet the load requirements. The grid structure form is also used.

There are two forms of practice:

① Overall lighting: that is, the structure in which everything above the grid is made into a lighting cover. As shown on the right.

② Partial lighting: That is, part of the grid above the grid is made into a lighting cover, and the other part is made into a structure of other insulation boards (color steel sandwich roof panels are commonly used). As shown in the picture below right. B in the picture is the design gutter width