However these shingles are not run entirely through the valley area but rather the center of the metal valley is left exposed.
How to shingle a roof valley.
In order to shingle this kind of roof valley a roofing professional has to install both roof faces at the same time which is quite slow.
Each successive shingle should be then placed with a six inch overlap or until the adhesive strip contacts the bottom of the shingle tabs.
Stop nailing 6 inches from the center.
In addition it is important to avoid nailing the shingles through the valley metal.
Extend the 3 tab shingles on one of the roof s planes past the valley at least 12 inches.
The open woven and closed cut methods are demonstrated.
Lay one and two tab shingles as you near the valley so full size shingles will run across the valley.
Valleys are a prime leak area so it s important to be careful.
The open woven and closed cut methods are demonstrated.
To shingle out of the valley with laminated shingles lay a shingle down as a gauge and mark the corner at the bottom left and top right of the roof.
Snap a chalkline 2 to 3 inches past the valley center on the top layer of shingles.
Shingle the other side of the valley the same way.
From this starter shingle continue moving up the valley roof.
Continue until you reach the top edge of the valley roof.
The next shingle should be directly atop the first one.
As the asphalt shingles are installed over the roof deck the shingles are extended into the valley.
Step 6 shingle valley.
I then move the shingle to the uppermost course on the roof plane line up the mark on the shingle with the valley center and again mark the corner.
Secure all of the 3 tab shingles to the roof plane with the 1 inch roofing nails using the local building codes as a placement guide except for the shingles covering the flashing material.
Gaf mastering the roof chapter 12 this video demonstrates the proper installation technique for installing roofing valleys.