Open Cut Roof Valley

For an open valley a sheet of metal usually steel sometimes copper is fastened to the roof deck.

Open cut roof valley.

The shingles are then cut out of the valley area opening the surface of the valley lining to water run off and the environment. The seam where the two planes of roofing meet are aesthetically woven together to form an interlaced design which creates a seam that matches the contours of the roof. No one of this affirmat. However it is said that provided the rest of the roofing shingles were properly installed and are performing properly open valleys will perform better over time than closed valleys.

The metal is usually pre painted to best complement the shingles color blend. The cut edge then is sealed with roof cement. An open valley relies on metal flashing for protection. Some homeowners do not like the look of open valleys while others feel the metal accentuates the roof s shape particularly if copper or painted flashing is used.

Can t afford standing seam metal though so it will be mid grade architectural asphalt shingles installed with meticulous detail. I m in a mixed humid climate zone 4a. Roof is 5 12 slope with a couple of valleys. An economical version uses two layers of roll roofing for the lining which should last as long as an asphalt roof.

Open valleys may be susceptible to water backup if the cut off shingles are not properly trimmed potentially causing roof leaks. A roof using the open valley style involves placing a v or w shaped piece of metal usually galvanized or sometimes copper in the seam of the valley and then covered with a base sheet such as 30lb. One nail goes into the top section of the shingle where it covers the valley metal. A chalk line is then used to strike a line from the top of the valley to the bottom of the valley.

With a heavy gauge noncorrosive metal lining open valleys are the most durable valley and the most costly. That flashing is left exposed so the roof has visible lines of metal running down the valley. And either an organic or modified underlayment depending on whether tiles or shingles are being. I finish the cut edge with a double bead of roof cement the same as for the open metal valley.

In this video i show you how i do the valleys on a shingle roof. Open valley shingle installation. With sheet metal protecting the lower layer of shingles the shingles on top are cut back to the line right. At flashing wall details.

I want my roof to be as leak proof and long lasting as possible. Many roofers cut the shingles across because they say it s safer. With an open valley a strip of metal will be visible on the roof wherever two opposing roof planes meet. See our discussion of alternative flashing materials found.

When all the shingles are installed to the guide line the cutline is resnapped left. I m trying to decide on the best way to do the valleys open metal valleys or closed cut ones.