Flashing In A Roof Valley

Roof mastic applied along sides of valley flashing.

Flashing in a roof valley.

There are two common methods for completing the flashing of a valley in a shingle roof system. From drip edge to valley flashing. Closed valleys or open valleys. Closed cut valley fully replaced with new metal valley flashing.

One of the details that varies between homes is the method of flashing the valley areas of the roof. Lay one and two tab shingles as you near the valley so full size shingles will run across the valley. Shingle the other side of the valley the same way. This collection of 18 articles animations and videos identifies the critical roof flashing areas.

Stop nailing 6 inches from the center. Roof one side of the valley running the shingles across it. Punctures in the center of the valley. Properly sized and installed valley flashing is key to channeling water safely off the roof.

Avoid the following common errors. Some homeowners do not like the look of open valleys while others feel the metal accentuates the roof s shape particularly if copper or painted flashing is used. To understand what makes a valley either closed or open it is important to understand how a valley is constructed. Snap a chalkline 2 to 3 inches past the valley center on the top layer of shingles.

Valley flashing is metal or sometimes peel and stick material that protects an important area on the roof where two slopes come together to form a valley. Fasteners placed in the exposed center area.