Open Or Closed Roof Valley

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

Open or closed roof valley.

An open valley has a gap usually about 6 inches between the tile or shingles at the valley area. For an open valley a sheet of metal usually steel sometimes copper is fastened to the roof deck. A closed valley is where the tiles or shingles are butted up against each other in the center of the valley. 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.

The metal is usually pre painted to best complement the shingles color blend. An open valley can easily and quickly shed ice and water. Open valleys may be susceptible to water backup if the cut off shingles are not properly trimmed potentially causing roof leaks. An open roof valley meanwhile is a flashing method in which a sheet of pre bent metal is installed after the valley lining is placed.

However open valleys may be susceptible to water back up along the top of the cut off shingles in the valley if not properly trimmed potentially causing roof leaks. The roofers apply the shingles cutting and sealing the ones that overlap the metal. Open valleys are excellent for preventing moisture from entering through the lining and protecting your roof from the humidity of the outside air. The only type of valley that is unacceptable is the woven valley.

Closed valleys are very vulnerable to mechanical damage. Although the open valley is recommended by the manufacturer closed valley is acceptable. 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. 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.

Closed valleys may have a tendency if not constructed properly to channel water under the shingles laid over the bottom layer of shingles. 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.