Water has a small chance of even getting up under the woven valley shingles even though it flows in either direction.
Roof valley shingle weave.
Closed valleys or open valleys.
There are two common methods for completing the flashing of a valley in a shingle roof system.
All of the shingle rows will need to be lined up correctly.
A woven valley shingle installation is one where the shingles from both sides of the roof valley extend over the valley and weave together overlapping courses alternately.
Weaving a shingle valley by dunn contracting 727 410 5717 james dunn.
One of the details that varies between homes is the method of flashing the valley areas of the roof.
Here we have a laminated shingle roof that has been installed with a woven valley detail.
The woven valley shingle installation method does not call for roofing cement relying instead on the weave pattern to protect from water infiltration.
Woven valleys should only be used with strip shingles.
So if you are installing a woven valley you must push the shingles snugly into the valley while not nailing within six inches of the valley center.