Open Valley Roof Flashing

Step 9 cut corners and apply cement dub cut the top layer shingles see step 4 in open metal valley above.

Open valley roof flashing.

When properly installed w valley flashing will reliably channel run off water down the roof and into the gutter. 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. Roof valleys are like gutters with a steep pitch but the stakes are higher for valleys than they are for gutters in a previous video we covered how to flash roof edges before shingling. Extend entire width of flashing completely to the bottom of the roof valley.

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. Be sure to check local building codes to ensure you have the proper width for your application. 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. Lile points out that valleys lined with roll roofing are not as durable.

To splice the pieces add roofing cement to the lower piece and install the upper piece with at least a six inch overlap. That flashing is left exposed so the roof has visible lines of metal running down the valley. Product overview w valley flashing protects the critical area of your roof where two slopes come together to form a valley. An open valley relies on metal flashing for protection.

This valley flashing material can be manufactured from any metal that will resist the effects of weather acid rain and other contaminants. 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. In comparison to a closed valley an open valley adds another layer of lining into the valley. 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.

Roofers on the other hand often prefer an open valley because they feel it is more practical. Flashing a humpy old roof valley requires a little give and take and a backup plan.