Steel roofs, just like all others, need to avoid holding too much moisture in order to last as long as they possibly can. When a roof needs a drainage point, a metal roofer will often install valley flashing. This flashing allows rainwater and moisture from melting snow to run off the metal roofing and into a weather tight channel that can divert the moisture off the roof. When discussing a metal roof installation, ask your installer if your building can benefit from a roof valley.
The internal joint or valley is fabricated from a polymer coated flat sheet. A V-shaped valley gutter with raised edges is placed onto the strapping and attached to the strapping with cleats and galvanized nails. The width of each side of the valley gutter is from 12" to 24", depending on the roof incline and pitch. The valley gutter may also be installed directly on the moisture barrier, and not on the strapping. In this case it will have a complex, indented profile.
After installing the roofing tiles, the valley is covered by a decorative cover strip. It is mounted using self-tapping screws, catching the peaks of the tile profile every 12-18". The width of the cover strip is 4" to each side from its axis.
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