Roofing Valley Closed Cut

When it comes to your closed valley design there are a few options.

Roofing valley closed cut.

For a closed valley shingles are installed across the joint where planes intersect. From the valley center. If you are looking to install shingles you might want to consider the closed cut valley method. Shingles are overlapped across the valley on alternative slopes.

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 essential to only use whole not cut shingles during this step. As you install roof shingles on the second roof plane you allow them to lap over the valley on top of the first shingles. Shingles are first installed on the side of the valley with a lower slope.

In general the closed cut valley method implies stretching one side of the shingles beyond the valley while those on the other side are trimmed. With a closed cut valley there s no need to shingle the two roof planes at the same time. Once covered the contractor moves to the side with a higher slope. With each new course roofing shingles continue up the valley.

I begin the second side the side that will be cut by snapping a cutline 2 in. In that case it wouldn t be a truly no cut valley but it would be faster than diagonally cutting each shingle. It is popular because the two roof planes do not need to be shingled at the same time. I think i first learned of the system reading a bundle of tamko shingles about 22 years ago and have used it frequently since.

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. Plus cutting the closed cut valley shingles can happen after the rest of the roof is shingled. Tamko is the only shingle manufacturer that shows the no cut shingle valley process in their installation instructions.