How To Install Valley Flashing On A Metal Roof

Install an underlayment centered in the roof valley.

How to install valley flashing on a metal roof.

Install synthetic roofing underlayment or felt paper according to manufacturer specifications and then install the first piece of valley flashing. Roof one side of the valley running the shingles across it. Shingle the other side of the valley the same way. Flashing should be installed in all of the valleys.

Lay one and two tab shingles as you near the valley so full size shingles will run across the valley. Open valleys have metal flashing to protect this critical area of the roof. Stop nailing 6 inches from the center. The edge of the roof has thin metal flashing that helps water drip off the roof without damaging the home or causing a leak.

The top joinery of both valleys when they meet on the same plane of roof is shown here. Some homeowners do not like the look of open valleys while others feel the metal accentuates the roof s shape particularly if copper or painted flashing. Then install a non corrosive metal valley flashing of 24 minimum width. W type valley flashing is more rigid for handling so it stays straight and it stops waler rushing down one side of a roof from rushing back up the other side.

Lap successive sheets of metal flashing a minimum of 12 inches and seal laps. Snap a chalkline 2 to 3 inches past the valley center on the top layer of shingles. When installing metal valley flashing there are a few things to keep in mind from cutting metal roofing to sealing the flashing. Metal valley trim also known as metal valley flashing is beneficial because it drains water away from the structure of your metal building which helps prevent moisture damage.

I have my valley custom made with water trough to help with leaking b. While some skylight manufacturers include flashing in their products sometimes roofing professionals have to create it or purchase it separately. An open valley relies on metal flashing for protection. Recommended procedures of basic valley flashing installation.