1. Before construction, carefully inspect the metal roof to ensure that it is firm, clean, rust free, and free from freezing. If it does not meet the above conditions, the following measures should be taken:
① Replace rusted firmware and add firmware in appropriate locations;
② Grind the rusted area clean with rust removal sandpaper until it shows the true color of the metal, and then apply a layer of anti rust paint.
③ Remove frozen objects, dust, and other dirt.
2. Determine the areas to be waterproofed: generally, the following areas of metal roof panels need to be waterproofed: horizontal lap, vertical lap, fan outlet, pipes extending out of the roof, air conditioning pipes, around daylighting panels, gutters, ridges, joints between metal plates and parapet, screw fasteners and other weak points of metal roof waterproofing.