Open Valley Roof Flashing

How to flash an open valley with w type valley metal.

Open valley roof flashing.

Fold the top of the flashing over the ridge and nail it off every ten inches or so along the outer edge of the flashing now this valley will carry water off the roof and away from the house. To splice the pieces add roofing cement to the lower piece and install the upper piece with at least a six inch overlap. Extend entire width of flashing completely to the bottom of the roof valley. Step 9 cut corners and apply cement dub cut the top layer shingles see step 4 in open metal valley above.

Roofers on the other hand often prefer an open valley because they feel it is more practical. That flashing is left exposed so the roof has visible lines of metal running down the valley. This valley flashing material can be manufactured from any metal that will resist the effects of weather acid rain and other contaminants. Cut bottom of flashing so the entire width of the valley flashing extends approximately 1 2 to 3 4 over the fascia trim board along eaves the following photos illustrate removal and replacement of a closed cut valley with new open metal valley.

In comparison to a closed valley an open valley adds another layer of lining into the valley. Pros and cons of a closed valley roof architects often prefer closed valleys to open valleys as they feel that it gives a home better architectural appeal. Nrca lile recommends that roof valley flashing metal for open roof valleys should be 26 gauge 0 45mm galvanized steel or equivalent noncorrosive nonstaining metal. Product overview w valley flashing protects the critical area of your roof where two slopes come together to form a valley.

Be sure to check local building codes to ensure you have the proper width for your application. Lile points out that valleys lined with roll roofing are not as durable. An open valley relies on metal flashing for protection. Flashing a humpy old roof valley requires a little give and take and a backup plan.

Slip a piece of sheet metal flashing under the top layer of shingles to protect the bottom layer in the valley while you cut the shingles with a hook blade. After the self adhering underlayment is installed across the valley a pre bent metal valley lining is installed.