Roofing Valley Transition

How to seal metal roof valley.

Roofing valley transition.

At the roof transition shown in. 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. 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. Cut the panels from the ground instead of on the roof to avoid damaging the roof with the debris.

Take care not to place any fasteners in the exposed center area of the metal flashing. Valleys are prone to collecting leaves particularly if someone sets up an antenna at the base of the valley. 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. Fold the top over the roof ridge and cut the bottom along the drip edge metal.

Best practices for sealing the metal roof valley vary based on the slope of the roof. First clean the debris out of the valley including sawdust nails and whatever else is in there. With a clean valley you can lay down some peel and stick roofing membrane. 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.