I'm going to have a 3-tab composition roof replaced. Most of the roofers here use 90# rolled roofing in the valleys. But one told me he uses 20" metal roofing in the valleys then overlays it with the felt then with rolled roofing. Is either method preferred? Thanks.
I really don't know but I'd bet on the metal/felt/90#
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On 04 Jun 2004 05:09:02 GMT, snipped-for-privacy@aol.comjk.net (GarySport) scribbled this interesting note:
By us the 90# roll roofing used as valley roll and then overlaid with felt is the preferred method. The 90# gives you 36" if coverage instead of 20" and better conforms to the shape of the valley.
More important than the variety of valley roll used is proper installation of the shingles in the valley. If it is to be a closed valley then the uppermost corner of the top shingle must be cropped per the instruction on the shingle wrapper. It may not seem like a big thing, but that little uppermost corner of the shingle is enough to divert a significant amount of water under the shingle where it can laterally travel far enough to get in under any valley roll and cause significant damage over time. An open valley will require both uppermost corners of the shingles on both sides of the valley to be cropped in a similar fashion. A closed woven valley is a different animal and must be assembled first one shingle on one side, then one shingle on the other side for maximum effectiveness.
Good luck.
-- John Willis (Remove the Primes before e-mailing me)
Definitely use the metal valley followed by the felt and then bitumen roll roofing. That's a good system. If you want to make it even better have the roofer cover the sheathing joints where the meet in the valley with a secondary waterproofing layer (AKA 'Peel and Seal'). Then even if the valley metal fails you'll still have protection from water intrusion.
John Willis wrote:snip>More important than the variety of valley roll used is proper
divert a significant amount of water under the shingle where it can laterally travel far enough to get in under any valley roll and cause significant damage over time....snip
John Willis, it's so nice to hear of a roofer who's conscious of trimming the "ears"! That little trick works wonders. The metal, felt and 90 lb. seems kinda redundant, but if the price is right, it'd pay off as soon as someone stepped in the wrong place at the wrong time. The installer should be conforming the 90 lb. and shingles as best they can to the valley to help avoid that scenario. Oh, and keeping the fasteners at least 6 inches away from the valley centerline. Tom Someday, it'll all be over....
On 04 Jun 2004 22:16:06 GMT, snipped-for-privacy@aol.comEDY (Tom) scribbled this interesting note:
I could try to tell you the number of times I've repaired this very problem, but I probably couldn't count that high!:~)
-- John Willis (Remove the Primes before e-mailing me)
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