The valley flashing should already be in place. Shingles on the intersecting roof surfaces may be applied toward the valley from both roof areas simultaneously or each roof area may be worked separately up to a point about 3′ from the center of the valley and the gap closed later.
Regardless of which procedure is followed, apply the first course along the eaves of one roof area up to and over the valley with the last shingle extending at least 12″ onto the intersecting roof. Then apply the first course onto the intersecting roof along the eaves and extend it across the valley over the top of the shingles already crossing the valley and at least 12″ onto the other roof surface. Apply successive valley shingles over each other as shown in (Figure 6.19). Press each shingle tightly into the valley and follow the same nailing procedure as the closed valley.
