Corrosion resistance
If you buy a coat that you expect to last for the next five years, but the zipper breaks after a couple of months, you are likely to be disappointed. Very disappointed.
This can happen in construction as well. The secret to sustainable construction lies in ensuring that all parts of the structure can withstand ageing for equally long. Although one might imagine that all roofing screws resist rust for as long as the roofing sheet, this is not the case.
According to the regulations, a roofing screw must be suitable for the material being fastened (SFS-EN 1993-1-3 + AC), and the roofing screw and roofing sheet must have similar corrosion resistance (SFS-EN 1090-2+A1). Steel roofing is made of galvanized, primed and top-coated steel, so the roofing screw must also be made of galvanized, primed and top-coated steel. However, the roofing screws available on the market usually have only one coat, namely a top coat. Read more about the coating thickness of roofing screws.
According to the regulations, the use of stainless steel with structural steel should be avoided when fastening steel structures, as it can form a corrosion couple, causing the sheet roofing to corrode. Read more.