The use of bad self -tapping screws
As a result of the use of such screws, the fasteners of fasteners will occur, which is why moisture will fall under the roof. Then corrosion of metal sheets in the places of fastening may begin. For fasteners of metal tiles, professionals advise self -tapping screws 4.8×28 (4.8×35) from stainless steel or high -quality carbon steel coated from corrosion. Such self-tapping screws have washers with EPDM-laying (strong elastic rubber, resistant to chemical and temperature effects) and heads covered with paint. To check the quality of the screw, you need to compress the self -tapping screw with pliers. On a high -quality screw, a rubber gasket and paint will remain intact.
