Valleys are created where two roof slopes meet.
Over valley roof.
Overlap metal roof valley sections by 12 inches and seal the lap with a flexible sealant such as polyurethane or butyl on roofs shallower than 5 12.
Extend entire width of flashing completely to the bottom of the roof valley.
Because of the sheer amount of water being navigated through this section your valleys need to be properly sealed.
Open valleys and closed valleys.
Water collects in a valley to flow off the roof.
The valleys on many older houses comprise layers of roofing paper which can deteriorate over time.
Find out the differences before you talk to a roofing expert.
Pros of woven valley shingle installations.
A roof valley is formed where two roof slopes meet.
Cut bottom of flashing so the entire width of the valley flashing extends approximately 1 2 to 3 4 over the fascia trim board along eaves the following photos illustrate removal and replacement of a closed cut valley with new open metal valley.
Woven closed cut and open.
On jul 10 2010 a woven valley shingle installation is one where the shingles from both sides of the roof valley extend over the valley and weave together overlapping courses alternately.
Lay one and two tab shingles as you near the valley so full size shingles will run across the valley.
There are two methods for sealing valleys.
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.
Your choice of valley installation method is critical because when improperly installed valleys are risks for serious leaks.
With a clean valley you can lay down some peel and stick roofing membrane.
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.
Essentially there are three main ways to shingle a roof valley.
All of the shingle rows will need to be lined up correctly.
Roof valleys are troughs that discard runoff water where two sections of sloped roof meet.
Stop nailing 6 inches from the center.
Roof one side of the valley running the shingles across it.
Shingle the other side of the valley the same way.