Open Or Closed Roof Valley

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

Open or closed roof valley.

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. The only type of valley that is unacceptable is the woven valley. Closed valleys protect the roof lining from abrasion that water run off would cause and are therefore quite durable options.

If you have a shingled roof as most torontonians with a sloped roof tend to have then you will have one of two kinds of valleys on your home. 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. Open valleys are excellent for preventing moisture from entering through the lining and protecting your roof from the humidity of the outside air. The main advantage of closed valleys is that they protect the roof from snow and ice build up however in florida this is not an issue that needs to be considered.

Closed valleys may have a tendency if not constructed properly to channel water under the shingles laid over the bottom layer of shingles. It is always a good idea to check with the manufacturer or a certified installer of the product such as ourselves. 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. Open valleys may be susceptible to water backup if the cut off shingles are not properly trimmed potentially causing roof leaks.

The metal is usually pre painted to best complement the shingles color blend. 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. An open valley can easily and quickly shed ice and water. Closed valleys are very vulnerable to mechanical damage.

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 roofers apply the shingles cutting and sealing the ones that overlap the metal.