Closed Valleys
#2
01-01-09, 07:27 AM
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The place to start for comp shingle questions is the Master Shingle Applicator's Manual:
3 tab shingles, closed valley is on pp 118
Laminated shingles, closed valley is on pp 150
Those are "closed-cut valleys", it's also possible to do "woven-valleys"
The alternative to a closed valley is an "open-valley", in this case the shingles are cut to both sides of the center of the valley and rest on roll roofing or metal flashing laid in the center of the valley.
3 tab shingles, closed valley is on pp 118
Laminated shingles, closed valley is on pp 150
Those are "closed-cut valleys", it's also possible to do "woven-valleys"
The alternative to a closed valley is an "open-valley", in this case the shingles are cut to both sides of the center of the valley and rest on roll roofing or metal flashing laid in the center of the valley.
Last edited by Michael Thomas; 01-01-09 at 08:06 AM.
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01-01-09, 08:03 PM
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Originally Posted by tinner666
The picture of the open valley shows the wrong ay to cut the shingles. Interesting. It should show those tops being cut off parallel to the rafters.- Thanks
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01-03-09, 06:34 AM
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#6
01-03-09, 06:39 AM
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If you also cruise to 'Water Tracks', you'll find a 40 year old valley done that way for 2 different roof that never leaked. It's only 12" metal and ice dams apparently never caused it any issues either. On yeah. It never had any underlay under it either.
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01-03-09, 06:47 AM
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Interesting. In this thread, http://forum.doityourself.com/roofin...-addition.html, they have an illustration showing how to cut the shingles at a 'reverse 45 angle'. I've had to repair those too. The angle will direct water under the shingles in heavier rains much like not clipping at all.
