1、The left is the Division I recommended the layout, the right is not recommended by our Secretary.

2、I recommend the lighting board and the steel plate is the best overlap from the roof to the eaves of the long lap, or from the roof to the house in the purlin, the reason is as follows:
（1）、The plate is different from that of the steel plate. It is well known that the steel sheet is cold rolled and its corner angle is usually small. The lighting plate is thermosetting, the corner is usually too large (if the angle is too small, the stress will be great, storage and use are not very good). Which makes the lighting board buckle in the steel plate is more appropriate.
（2）、For the above reasons, the lighting board is usually slightly larger than the steel plate. Making the lighting board buckle in the steel plate on the more fit. If there is a steel plate (especially the angle of type Ⅲ) lap in the lighting board, buckle together will not be so fit, and even lead to the lighting board crest is fractured, causing leakage hazards.
（3）、Continuous lighting panels horizontal arrangement should not be too wide, because in the construction process, due to the lighting is too wide, the construction workers across the lighting belt when the trampling behavior, stampede on the one hand is likely to cause cracking of the lighting board, resulting in Leaking; even worse, the lighting board step on the pass, causing staff to fall, the formation of security incidents
It will cause great regret! In summary, I recommend the Secretary to pass the lap, and the horizontal should not be too wide (recommended a lighting board no more than one meter).