How To Flash A Roof Valley

Now nail this first flashing at both its far ends.

How to flash a roof valley.

Use 1 inch galvanized roofing nails. Stop nailing 6 inches from the center. Remember to caulk the underside of the flashing with a sealant. Lay one and two tab shingles as you near the valley so full size shingles will run across the valley.

One common method is to lay the edge metal under the eaves membrane and over the rake. Install valley battens on both ends of the roof valley then attach first flashing 3 4 inches over the roof flange and another 3 4 inches over the fascia if any is present. Make sure that the end of the flashing panel is perfectly in line with the edge of the roof. Shingle the other side of the valley the same way.

Details concrete masonry roofing wrb flashing. Roof one side of the valley running the shingles across it. Snap a chalkline 2 to 3 inches past the valley center on the top layer of shingles. Attach the flashing panel in place at the bottom.

Fold the top of the flashing over the ridge. Cut the bottom edge and fold it down over the drip edge. Lay the flashing down in the roof valley and start at the lower end of the roof. To splice the pieces add roofing cement to the lower piece and install the upper piece with at least a six inch.

Two ways to flash roof edges.