Open Valley Roof Vs Closed

It is always a good idea to check with the manufacturer or a certified installer of the product such as ourselves.

Open valley roof vs closed.

A closed valley is where the tiles or shingles are butted up against each other in the center of the valley. Closed valleys are very vulnerable to mechanical damage. Open valley when compared to a closed valley and open valley adds an additional layer of lining. The metal is usually pre painted to best complement the shingles color blend.

For an open valley a sheet of metal usually steel sometimes copper is fastened to the roof deck. Once the shingles are installed they don t run through the valley area. I further feel that an open metal valley would flush faster without wearing away the granules. 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.

What is an open valley roof. 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. In looking at the fabral metal roofing supply catalog it has a valley flashing that from the end looks like a w. This leaves a metal strip or line on the surface of the roof that serves as the valley line.

Regardless of open or closed this of course presumes that a grace water ice membrane is used. After the underlayment is placed a pre bent metal valley lining is installed. After the self adhering underlayment is installed across the valley a pre bent metal valley lining is installed. In comparison to a closed valley an open valley adds another layer of lining into the valley.

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. Although the open valley is recommended by the manufacturer closed valley is acceptable. Since it isn t bogged down by the friction shingles invariably create. Proponents of the open version say that an open flashing allows the rainwater to move away from the roof faster.

An open valley has a gap usually about 6 inches between the tile or shingles at the valley area. The only type of valley that is unacceptable is the woven valley.