Water collects in a valley to flow off the roof.
Shingle roof valley.
The valley area of a roof the straight lines formed when two different planes of the roof meet is a critical area that handles a tremendous amount of water run off.
From the stepped off main part of the roof run shingles into the valley and cut them square from where the bottom corner intersects with the shingles nailed along the valley line.
Your choice of valley installation method is critical because when improperly installed valleys are risks for serious leaks.
The open woven and closed cut methods are demonstrated.
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.
Valleys are a prime leak area so it s important to be careful.
Woven closed cut and open.
Place the nails along the edge of the valley metal not into it.
How to shingle roof valleys gaf mastering the roof chapter 12 this video demonstrates the proper installation technique for installing roofing valleys.
Valleys are typically found where gable dormer roofs meet the main roof or when a house has angled wings or additions where two roof sections in different planes meet.
One nail goes into the top section of the shingle where it covers the valley metal.
Essentially there are three main ways to shingle a roof valley.