Metal Roof Screws In Ridge Or Flat

Valid arguments can be made for both preferences.

Metal roof screws in ridge or flat.

We do recommend it however. On metal roofing panels with ribs why would one drive screws through the flat part of the panel instead of through the top of the rib. The purpose of the purlins is to provide a solid foundation for the metal roofing panels and trim to be screwed to. As the screws are driven the washer presses against the metal roofing to form a water proof seal.

Purlins are non pressure treated 1 x 4 x 12 lumber that is installed on to the roof in a specific layout pattern and screw pattern. If the screws are driven correctly fastening through either the valleys or the ridges of the roofing is considered acceptable in this country. These panels have raised ribs. Your roof will have thousands of screw holes.

Having done several metal roofs since then i would say if you are an amateur screw on the flat with 1 1 2 screws. Quite often the screws are over tightened or under tightened and when this happens it creates leak points. The main cause of a leaking roof on a diy metal roofing installation is incorrectly fastening the screws. Screwing high on the rib is difficult for the amateur.

The directions for installing metal roofing panels that are attached by exposed fasteners give different methods for nails vs screws. My natural inclination would be to insert fasteners through the top of the rib so that the hole. It depends on the metal if it is coretin or any other corrugated metal no screws in the valley or flat part of metal if it is a tuffrib or deltarib put screws in the valley. Do all roofing projects require purlins.