To install the valley detail,
begin by chalking a centerline and a symmetrical line wider than the valley
as a reference to make sure the detail lines up properly. Make sure to clean off
all exposed remnant chalk lines. Using the eave as a guide, mark along the
underside of the valley to make your cut. After you cut the valley and cap the
diamond portion, hook the hem on the eave. Make sure the valley lines up and fasten.
It is very important that all the fasteners in the assembly are installed
straight and perpendicular to the roof surface. Ensure you provide for a
one-foot lap for any additional valley pieces, and align with your chalk line.
Use two continuous beads of an approved sealant approximately four inches apart
and four inches above the seam to create a gasket seal. Generally, the valley will
not allow water to infiltrate the system if a one-foot lap is used. Set one side
and work to the other. Step in the valley to make it tight. Once the top piece is
secure, the bottom piece has nowhere to go.
Once the offset cleat gets added to the system, it will secure the valley and
more fasteners will be added.