Roofing Valley Closed Cut

For a closed valley shingles are installed across the joint where planes intersect.

Roofing valley closed cut.

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. Once covered the contractor moves to the side with a higher slope. It is essential to only use whole not cut shingles during this step. 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.

I think i first learned of the system reading a bundle of tamko shingles about 22 years ago and have used it frequently since. Shingles are first installed on the side of the valley with a lower slope. Shingles are overlapped across the valley on alternative slopes. As you install roof shingles on the second roof plane you allow them to lap over the valley on top of the first shingles.

I begin the second side the side that will be cut by snapping a cutline 2 in. In summary during the installation of a closed cut valley you install the first roof plane s shingles into the valley. 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.

According to long time iko sales representative jeff tessaro closed valleys for residential construction have been popular since he was a roofing contractor in the late 90 s. Tamko is the only shingle manufacturer that shows the no cut shingle valley process in their installation instructions. The closed cut valleys are cheaper and commonly done in my area but they tend to wear out sooner due to the high volume of water in the valley washing away the protective grit on the shingles there before on the rest of the roof. Closed valleys may have a tendency if not constructed properly to channel water under the shingles laid over the bottom layer of shingles.

Plus cutting the closed cut valley shingles can happen after the rest of the roof is shingled. If you are looking to install shingles you might want to consider the closed cut valley method. With each new course roofing shingles continue up the valley.