With the influence of rainwater and moisture condensation, the most serious corrosion is the edge of dripping eave. The initial sign of incision corrosion is the tiny bubbles that are visible to the underside of the trimming, and over time, the bubbles spread to the whole edge. For part of the metal coating products, the bubble at a fixed rate of expansion until the edge near the board to produce “red rust”.
The bubble spreading rate of color coated products gradually decline with the increase of time. So the corrosion of colored corrugated roofing sheet is better than that of the regular coating products.
For the color coated steel sheet, CAMELSTEEL suggests that you don’t process strip or long trimming, because the trimming will be completely exposed on the environment. The manufacturer need to order the roll-in to process the colored sheet as required to avoid trimming exposure. And the edge of the whole width colored corrugated roofing sheet is protected by the galvalume layer and coating.
3. Roof panels and wall panels.
The corrosion of this part is weaker than that of dripping eave because there are no rainwater and moisture condensation. We should use full length plates as far as possible to reduce the exposure of end trimming.