Open Valley Roof Flashing

Extend entire width of flashing completely to the bottom of the roof valley.

Open valley roof flashing.

When properly installed w valley flashing will reliably channel run off water down the roof and into the gutter. In comparison to a closed valley an open valley adds another layer of lining into the valley. An open valley relies on metal flashing for protection. Step 9 cut corners and apply cement dub cut the top layer shingles see step 4 in open metal valley above.

To splice the pieces add roofing cement to the lower piece and install the upper piece with at least a six inch overlap. Lile points out that valleys lined with roll roofing are not as durable. This valley flashing material can be manufactured from any metal that will resist the effects of weather acid rain and other contaminants. 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.

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. How to flash an open valley with w type valley metal. 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 is used. Roofers on the other hand often prefer an open valley because they feel it is more practical.

Be sure to check local building codes to ensure you have the proper width for your application. That flashing is left exposed so the roof has visible lines of metal running down 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. 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.

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. Flashing a humpy old roof valley requires a little give and take and a backup plan.