Only nail at the edges with only enough nails to.
Shingle roof valley installation.
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.
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.
How to do it determine cuts.
Others start with a 3 inch wide.
This video demonstrates the proper installation technique for installing roofing valleys.
Some roofers cut the shingles parallel to the flashing s center ridge.
To secure the roof valley flashing nail it down carefully.
Ensure ice and water protector has been installed along the valley first.
The open woven and closed cut methods are demonstrated.