| Author | Message | ||
     Paul Mitsis |
I have proposals for a rebuild of my roof that give me a choice of open versus closed valleys. Is this anything aside from an asthetic choice? What are the advantages or disadvantages of each? Thanks | ||
| joe jenkins |
It's pretty much an aesthetic choice. | ||
| joe |
I might add that things such as water, snow, ice, and leaves exit an open valley faster than a closed one. | ||
| Walter Musson |
I agree with Joe,it's just personal preference.The high end jobs with an architect more often than not specify closed valleys.When using open valleys with copper there can be wear thru on the copper sheet becase of it's softness.I think thats why some prefer closed to open.I like the look of slate and copper together,but realize that longevity is a concern. | ||
| Tim Dittmar |
My experience is in the temperate South where roofs may be less steep w/o obvious consequence- my inspecting style(at least) was often freehand or with just a rope(as soon as I could rig it) and open valleys were a decided advantage. That was esp. so if wider than a shoe- it was possible to walk up a valley(less steep than the roof!) to gain the ridge/chimney/?. Yes, it's a matter of style, too- closed valleys seem more "other", "exclusive", ?. Well, you know! On the downside, closed valleys are more technically demanding- if a mistake is made in laying, it is demonstrably harder to look for it and find it w/o pulling the roof apart- felt underlayment may postpone the advent of a leak also, plus(the big one)- displace the point where the leak appears- this can aggravatingly happen with an open valley as well but the finding is so much simpler. Joe is correct about the self-flushing of an open valley(big issue with rusting metals of old). I've found that copper and acid rain can interact rapidly and valleys may fail in 30-40 years at least on a "spot" basis(consider s/s valley even if it requires painting to resemble weathered copper)- a strip of 30 lb felt between slate and copper valley(elec. insulation) is probably quite worth the little extra trouble as electrolysis speeds the failure- the open valley should also widen modestly as it descends, etc. Some "spec's" may require that valley metal not be nailed into when attaching slates- alot of that is in regard to expansion/contraction of copper(has a bad case of it)- I would tend to disregard most of that but do stress that cold-rolled(tempered?) copper sheet resists flexing/fatigue much better than soft or roll copper(don't use soft!)- further, shorter panels of break-bent valley will have less accumulated expansion stress. Most of these considerations(expansion, etc.) probably pertain to open valleys much more so as the closed valley is flashed(bibbed?)with postcard-sized pieces. Whew! There's lots more.... | ||
| joe |
Those are some of the reasons I like open valleys too: if the metal is strong enough (we typically use 20 ounce hardened copper, for example), you can walk all over it, and it makes it easy to move around on the roof if you can step in the valley. Also, leaks are easier to find on open valleys when they start to deteriorate. Closed valleys develop leaks too in the copper, usually right down the middle where the copper gets eaten away in holes or strips, but you can't see them without taking the roof apart. On the other hand, I like the look of closed valleys too. In fact, we're going to try installing more rounded *slate* valleys in the future, which have no exposed metal and can't be walked on (they're made of slate - I'll be doing an article on them in a future Traditional Roofing newsletter - already working on it). I'm going to remove a couple of the open stainless steel valleys on my house, which would last forever, and replace them with rounded slate valleys so I can try a couple of different styles. It's a 10:12 pitch, sea green slate. I may even offer the job as a roofing workshop. (By the way, we're doing a flat seam copper roofing workshop on March 9th - day long, but it's pretty well filled already). | ||
| Abby |
My roofer wants to use aluminum in a closed valley. Is copper or aluminum better here?...Thanks. | ||
| abby |
I should add, I'm in New York City and am replacing a slate roof with Slateline. So the roof has a pretty steep pitch. Is something else better than either copper or aluminum? |
