Open Valley Roof Vs Closed

Although the open valley is recommended by the manufacturer closed valley is acceptable.

Open valley roof vs closed.

Since it isn t bogged down by the friction shingles invariably create. Once the shingles are installed they don t run through the valley area. In looking at the fabral metal roofing supply catalog it has a valley flashing that from the end looks like a w. This metal lining can be made of any type of metal that is resistant to the effects of weather acid rain or other contaminants.

Proponents of the open version say that an open flashing allows the rainwater to move away from the roof faster. A closed valley is where the tiles or shingles are butted up against each other in the center of the valley. Open roof valley this is almost the same as the closed roof valley method except a pre bent metal valley lining is installed instead of a secondary roof underlayment. Closed valleys are very vulnerable to mechanical damage.

And while some homeowners may prefer the aesthetics of a closed valley the heavier and thicker the shingle the less likely it is to lie flat across a joint. This leaves a metal strip or line on the surface of the roof that serves as the valley line. I further feel that an open metal valley would flush faster without wearing away the granules. What is an open valley roof.

Regardless of open or closed this of course presumes that a grace water ice membrane is used. The only type of valley that is unacceptable is the woven valley. When you research this topic online you will likely find people who prefer one of these methods of the other and they will give their reason. After the underlayment is placed a pre bent metal valley lining is installed.

For an open valley a sheet of metal usually steel sometimes copper is fastened to the roof deck. An open valley has a gap usually about 6 inches between the tile or shingles at the valley area. Open valley when compared to a closed valley and open valley adds an additional layer of lining. The closed variation is a flashing that has been completely covered with shingles while in the open variation will have the flashing completely exposed to the elements.

Repairs to closed valleys are a lot more involved than working on an open valley as is re roofing or making changes to a portion of your roof in the future. In comparison to a closed valley an open valley adds another layer of lining into the valley.