A California valley is faster than cutting all of the shingles up a valley. With shingles bedded in cement, it can be exported to other states.
Here is Eric's method:
- Make sure the valley metal is straight before nailing it. Look down the ridge of the valley metal to make sure it is straight from top to bottom and nail it off.
- Snap a line on each side of the ridge top to bottom. Eric cites 1-1/4 inch. Some roofers like to make it wider at the bottom than the top for a nicer look.
- If you work somewhere other than a desert—like Los Angeles, where Eric lives and works—add a bead of roofing cement along the edge of the valley metal to bed shingles into.
- Align the bottom of a shingle along the chalk line, bed the shingle into the roofing cement, and nail it to the roof deck. Place the nails along the edge of the valley metal, not into it.
- 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.
- One nail goes into the top section of the shingle, where it covers the valley metal. The rest of the nails go in the nailing strip.
This method is a similar method to what Mike Guertin calls a Long Island Valley, which runs shingles from the first slope past the valley and up the second slope. Shingles are then bedded in cement going up the valley. The edges are finished in a similar fashion to Garcia's method. Roof cement should be dabbed under the shingle corners.
—Eric Garcia is a roofer and YouTuber in the Los Angeles area.