I am not from North America so here there is a lot more rain. But I am surprised to see some metal roofing systems where the iron sheets are screwed in the water channels. If the screws and washers lose their torque, it is inviting water to penetrate the building. If the sheets are screwed on the ridges, most water will be deflected away from the screws and while a little may penetrate in heavy rain, it wont usually be enough to cause a problem. Being a paint chemist in the past, I see corners being cut which will speed up deterioration. It is a must to properly paint or seal where the sheets come into contact (laps) as these areas are prone to rusting. Likewise paint or seal the underside of the iron (if not painted ) at the edges especially if near the beach. My iron decramastic roof rusted badly on tbe underside at the perimeter where water discharges into the gutter. Fortunately a roofing contractor sold me new tiles cheaper than I could buy used tiles from a recycling warehouse. It would have saved a lot of work if these few extra things had been done when the roof was laid.
I am not from North America so here there is a lot more rain. But I am surprised to see some metal roofing systems where the iron sheets are screwed in the water channels. If the screws and washers lose their torque, it is inviting water to penetrate the building. If the sheets are screwed on the ridges, most water will be deflected away from the screws and while a little may penetrate in heavy rain, it wont usually be enough to cause a problem. Being a paint chemist in the past, I see corners being cut which will speed up deterioration. It is a must to properly paint or seal where the sheets come into contact (laps) as these areas are prone to rusting. Likewise paint or seal the underside of the iron (if not painted ) at the edges especially if near the beach. My iron decramastic roof rusted badly on tbe underside at the perimeter where water discharges into the gutter. Fortunately a roofing contractor sold me new tiles cheaper than I could buy used tiles from a recycling warehouse. It would have saved a lot of work if these few extra things had been done when the roof was laid.
@stuartmclaren2402 this is a great point! Making sure there is no exposed metal will prevent premature panel deterioration!