Professional structural maintenance should be carried out at least once every two years. This is the highest priority routine work because rusting of metal structures destroys their strength and contributes to structural deformation.
Thus, the life-long serviceability of professional metal roofs can be achieved if they are maintained annually.
However, it should be remembered that damage may occur due to external factors (diverse load impact) or atmospheric conditions (ultraviolet radiation, rain, snow, temperature differences).
The fact is that the metal at the top of the roof is more exposed to atmospheric conditions than other parts. The top sheets are corroded twice as quickly as lower ones, which may lead to structural deformation (bending) of sheet profiles (lips); therefore, it should be periodically monitored, and if the roof has been exposed to hurricane-force winds or hail, then it may need to be replaced sooner.