Only few people are aware that the roof of the building we live in or use as a storage of our raw materials or factories today can be flooded. The flood means that the water cannot be drained in time due to the heavy rainfall and the angle of the roof is small and not be related with the length of the building.

For example, building A use the model TBR-760B. Such model has a low height of curling and the angle of the structure does not meet the standard which is less than 5 degree and such roof has a very long length (including the length of the roof sheet at the peak to the lowest in each interval). This make the roof cannot drain the water in time. Moreover, a hard rainfall blocks the water, so it cannot flow easily. When accumulated, it will have a chance to slip into the joints between the roof sheet. Because of this, we should choose other models for more height, or increase the roof’s degrees or reduce the length of each interval. These will help solving the flooded problem.