Roofing Valley Transition

Apply an approximately 3 inch width of asphalt roofing cement along the sides of flashing and embed shingles in mastic clip the top corner of shingles along valleys to keep water flow toward center of valley.

Roofing valley transition.

Valleys are prone to collecting leaves particularly if someone sets up an antenna at the base of the valley. Best practices for sealing the metal roof valley vary based on the slope of the roof. Valleys are typically found where gable dormer roofs meet the main roof or when a house has angled wings or additions where two roof sections in different planes meet. The valley area of a roof the straight lines formed when two different planes of the roof meet is a critical area that handles a tremendous amount of water run off.

Cut the panels from the ground instead of on the roof to avoid damaging the roof with the debris. If repairs are needed the contractor has to remove and then reweave multiple shingles to replace a single one. First clean the debris out of the valley including sawdust nails and whatever else is in there. In order to shingle this kind of roof valley a roofing professional has to install both roof faces at the same time which is quite slow.

At the roof transition shown in. Low slope roofs slope less than 3 12 use tape sealant between the valley trim and the panel. With a clean valley you can lay down some peel and stick roofing membrane. The lower roof unavoidably slows down water drainage and when the valley is clogged a significant amount of water coming down that valley will tend to spread out and back up under the shingles.