A valley is an angle formed by the intersection of two sloping roof planes to provide water runoff. Because of the amount of water passing through that area of a roof, it is important to consider how the area will be protected when replacing an asphalt shingle roof.
There are different methods for shingling the area with dimensional asphalt roofing material. Closed cut valleys are most popular aesthetically. In a closed-cut valley application, shingles from one side of the valley extend across the valley while shingles from the other side are trimmed back a few inches from the valley centerline. Any flashing is not exposed. When using the open-cut valley roofing method the flashing is visible. Open-cut valleys may be used to create visual interest or enhance features on some design styles.
Some contractors will use ice and water shield under the shingles, others will choose to install metal flashing. Further, some contractors will install both for extra protection. A professional roofing contractor will consider many factors and make a recommendation as to the best method and style for the specific project. A detailed estimate will include these recommendations.
Craig Gouker Roofing has been installing quality residential roofing in South & East Pittsburgh since 1991 and is the expert in shingle roof replacement.