The lowest of these valley shingles is cut back at an angle in line with the lowest course line.
Roofing procedure valleys.
Roof installation how to shingle a valley hd by roofrepair101 more about roofing at.
Once this course is laid you can begin snapping horizontal chalk lines up the roof to ensure straight rows.
Roofers on the other hand often prefer an open valley because they feel it is more practical.
Then i install a line of shingles up the valley with the top edge aligned with my snapped line.
Your choice of valley installation method is critical because when improperly installed valleys are risks for serious leaks.
Tear off the old shingles.
Water collects in a valley to flow off the roof.
Apply an approximately 3 inch.
Next i smear roof cement a couple of inches away from my snapped line.
Apply two beads of roofing cement to attach the top layer shingles to the bottom layer shingles.
Start by laying all shingles on one side of the roofing and stretch it across the valley.
This video demonstrates the proper installation technique for installing roofing valleys.
The open woven and closed cut methods are demonstrated.
Away from the valley center just as i did with the closed cut valley.
When i ve finished shingling the first roof plane i snap a chalkline 2 in to 3 in.
Draw a 2 inch self stick flashing down the center.
Fasten the shingles about 6 inches away from the centerline on both sides.
Use four roofing nails per shingle as indicated on package instructions six nails in high wind areas.
Also apply cement to attach the top layer shingles to each other see steps 5 and 6 in open metal valley above.
Stretch it about 12 inches across the centerline.
Make sure to expose 5 in.
Essentially there are three main ways to shingle a roof valley.
Install an underlayment centered in the roof valley.
Then install a non corrosive metal valley flashing of 24 minimum width lap successive sheets of metal flashing a minimum of 12 inches and seal laps.
The reason that many roofers like an open valley is that they feel that tree leaves and needles will more easily slide down or wash down an open valley when it rains.
In the past i ve used several different methods to prepare a valley including lining the valley with aluminium coil flashing or roll roofing and even cementing together layers of 30 felt paper with asphalt roof cement a messy job.
Woven closed cut and open.
Architects often prefer closed valleys to open valleys as they feel that it gives a home better architectural appeal.
A roof valley is formed where two roof slopes meet.