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.
Open valley roof flashing.
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.
Stop nailing 6 inches from the center.
Extend entire width of flashing completely to the bottom of the roof valley.
Lay one and two tab shingles as you near the valley so full size shingles will run across the valley.
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.
There are two common methods for completing the flashing of a valley in a shingle roof system.
To splice the pieces add roofing cement to the lower piece and install the upper piece with at least a six inch overlap.
Roofing shingles are installed then cut and sealed where they overlap the metal channel.
That flashing is left exposed so the roof has visible lines of metal running down the valley.
Open valley shingle installation.
W valley flashing protects the critical area of your roof where two slopes come together to form a valley.
Closed valleys or open valleys.
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.
Roof one side of the valley running the shingles across it.
The metal is usually pre painted to best complement the shingles color blend.
One of the details that varies between homes is the method of flashing the valley areas of the roof.
Shingle the other side of the valley the same way.
The following photos illustrate removal and replacement of a closed cut valley with new open metal valley shingles.
To understand what makes a valley either closed or open it is important to understand how a valley is constructed.
Flashing a humpy old roof valley requires a little give and take and a backup plan.
Be sure to check local building codes to ensure you have the proper width for your application.
Snap a chalkline 2 to 3 inches past the valley center on the top layer of shingles.
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.
An open valley relies on metal flashing for protection.
When properly installed w valley flashing will reliably channel run off water down the roof and into the gutter.
