1. The roof is a double-layer sandwich panel, and the joints of the roof are not waterproofed. Due to the thermal expansion and contraction caused by different roof materials, natural wind blows the vibration of the color steel plate, resulting in the opening of the roof joints. During heavy rain, the water penetrates into the thermal insulation cotton through the joint part. Because the lower layer is sealed, the water has accumulated in the thermal insulation cotton for a long time. The water flows down from high and concentrates on the cornice part. The protection is a weak part of the anti-corrosion of the color steel plate. Long-term dampness and no paint protection will cause serious rust.

2. Since the roof has not been thoroughly maintained and repaired, someone needs to work on the roof for a long time, and the baking paint itself has a low hardness. During the construction process, the scratching of the construction tools, the violent construction of the installed color steel plate and other factors are very likely to cause the roof paint to fall off. For a long time, due to the corrosion of acid rain, the oxidation of the natural environment, the part of the roof paint peeling off, from point to surface, starting infectious corrosion. If it is not repaired in time, it will cause a large area of the roof to rust and perforate, affecting the stability of the roof structure. . There are hidden safety hazards and it affects the normal progress of the roof.

3. When it rains, the rain will wash away the floating embroidery on the rusty parts and flow on the roof. The contact between the oxidized iron and the rusty iron accelerates the rusting of other parts, resulting in the appearance of flowing rust marks on the roof.

In the final analysis, the most important reason for the leakage of the color steel plate is that the roof joints are not properly waterproofed. The repeated repairs cause the original paint to wear and lose the anti-corrosion protection, and the water accumulation caused by the leakage accelerates the oxidation rate of the color steel plate, causing a large area in a short time Rusty.