Snap a chalkline 2 to 3 inches past the valley center on the top layer of shingles.
Open valley roof flashing.
One of the details that varies between homes is the method of flashing the valley areas of the roof.
Roof one side of the valley running the shingles across it.
Lay one and two tab shingles as you near the valley so full size shingles will run across the valley.
Closed valleys or open valleys.
Stop nailing 6 inches from the center.
An open valley relies on metal flashing for protection.
The following photos illustrate removal and replacement of a closed cut valley with new open metal valley shingles.
Flashing a humpy old roof valley requires a little give and take and a backup plan.
Extend entire width of flashing completely to the bottom of the roof valley.
Roofing shingles are installed then cut and sealed where they overlap the metal channel.
There are two common methods for completing the flashing of a valley in a shingle roof system.
To understand what makes a valley either closed or open it is important to understand how a valley is constructed.
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.
For an open valley a sheet of metal usually steel sometimes copper is fastened to the roof deck.
Shingle the other side of the valley the same way.
Be sure to check local building codes to ensure you have the proper width for your application.
How to flash an open valley with w type valley metal.
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.
The metal is usually pre painted to best complement the shingles color blend.
To splice the pieces add roofing cement to the lower piece and install the upper piece with at least a six inch overlap.
When properly installed w valley flashing will reliably channel run off water down the roof and into the gutter.
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.
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.
Lile points out that valleys lined with roll roofing are not as durable.
That flashing is left exposed so the roof has visible lines of metal running down the valley.
