I would appreciate any suggestions on the appropriate way to flash this intersection? We have three entry roofs like this on this house. On the other side of this house we have a larger addition on which we have already decided to do a California cut on both valleys. This little roof and 2 others join into the house over doorways. I wonder if copper valleys with raised ridge and very little copper exposure might be the way to go. Or copper valley with folded over edges and the copper ties. The shingles are architectural but lifetime, so they are a little heavier.
thanks
arthur
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You forgot to add your attachment.
Well it seems things have changed since I last posted with a picture. I'm using firefox 3.0.8. Can someone perhaps point me to a relevant previous discussion on attaching pictures? I cannot seem to remember anything. Thanksarthurhttp://www.thesmallbuildingcompany.com
For a basic pic, I just click the "attatch files" button at the bottom of the screen...next to "post" "preview" and "spell check".That will attach a link to a photo. Which is easy and works fine. If you want the image itself to show in your post then you must preview it, click your photo attachment, copy the address, revise, and add the <img src="paste image address here"> then be sure to check the HTML boxIf you are still having trouble, try "The Sandbox" by clicking "My Forums" at the top then go to "The Sandbox" forum where you can get help on posting and practice.DC
But basically you want to do this?:
View Image
is your question on which type of metal valley pan to use?
"v"shaped or "W" shaped?
what is a "california cut" anyway? Is it anything like a texas two-step or a clevland shuffle?
DC
Thanks DCYour question is correct. V or W?
What i'm calling 'california' cut is when one side of the valley shingles go up under the other which has a straight cut.Hopefully the entry roof valley in question is shown my pictures attached.http://www.thesmallbuildingcompany.com
Okay, I am still a bit confused but I will try my best.I prefer the "W" style metal valley pan (MVP) because the inverted "V" in the center slows the rain water from shooting back up the other side. I cut the shingles 4" from the center which leaves 4" under the shingles. Note that you cannot nail into the MVP so you don't want to hang too much over the edge of the pan. I dub and glue each shingle in the pan area. Now, the funny thing is that around here that "california cut" is called a "michigan valley" but properly called a "closed cut valley" and while they are the easiest and most popular, I don't like them because they are debris traps, they can rot easier from ice damming, and since there is nothing there to slow rain water, water may get under them in some weather conditions. I would recommend a woven valley instead. But here's where I am confused...Is that your house? Are the shingles already on the house and you want to add or retrofit? Are you asking about whether to expose the MVP or shingle over it? I use membrane under my MVP valleys and even a cali-cut valley has membrane.I hope I answered your question. If not please ask again in different words.BTW: copper valleys look good for awhile but are very $$$$$! a better option (especially on an older house) is to use a bronze painted look alike. Oh, and try checking out Taunton's book on roofing (for pro's by pro's Roofing, flashing & waterproofing). You should be able to find it at Home Depot or any good bookstore. It will give a better explanation that I can.DC
Thanks so much for your efforts. The picture is of a rehab we are doing. In process. We are re roofing it.I was asking about how much copper to expose on iether side of the W. I understand and agree with everything else you suggest. Funny thing about those names. I dont know who I got california cut from..I will write more later..arthurhttp://www.thesmallbuildingcompany.com
".......how much copper to expose...."about half.DC
sorry I forgot to attach a picture and now that its been so long since I did this I have forgotton how. Please stand by. :)
a W is best, and you should leave a coup[le inches exposed on each side, tending to less in high wind areas and more in places where tree debris is a problem.
As to the edges whether clean or a return fold depends a lot on pitch of roof and type of shingles, and how wide you make that W metal overall
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I would use a valley with only a center bend , locked onto a copper drip edge on the overhang eaves and rake.
I'd use a 18" sheet bent for 7" on the wall side , leaving 4" exposed , then 7" exposed on the overhang side.
It's much easier to lock the single bend valley on bottom , and the window at the top makes it easier there too.
You beat me to it. I 2nd that motion.http://www.quittintime.com/ View Image
Grant,
We think alike a lot of the time ! Don't know if thats good or bad !!!
Walter
Was that a motion or a notion?;)All that copper rubbing off on your two is what makes the minds follow the same electronic circles. Same windings, same armature, just different nameplates on the toolbody
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You sound like you've inhabited Sphere's body now !!!
Or is that Malo !
I didn't have any problems locking the W at the drip edge.At the top I have covered with step flashing or cap shingles; in his case I would cover the top with the top roof flashing over some sort of step flashing cuts and bends, and copious amounts of roofing caulk.I forgot to mention that the W adds quite a bit of rigidity to the pan that may otherwise set a bit wavy in the valley.DC
I didn't have any problems locking the W at the drip edge.
But, "V" valley is easier and takes much less time.
At the top I have covered with step flashing or cap shingles; in his case I would cover the top with the top roof flashing over some sort of step flashing cuts and bends, and copious amounts of roofing caulk.
Well, you've given several examples of ways to do it, none of which are the "only" way to do it and probably none are the "best" way, either.
Walter suggested using "V" valley to take the "fiddliness" out of the installation. "W" valley is useful where there are unequal slopes on either side of the valley, but has no real function other than that.
I forgot to mention that the W adds quite a bit of rigidity to the pan that may otherwise set a bit wavy in the valley.
More bends always add more rigidity, but if you clip your valley down rather than naling it, it won't get wavy.http://www.quittintime.com/ View Image
I agree a V would be an easier cut, but a W only requires two more cuts and two more bends; maybe two more minutes.At the top, yes there are several ways to do it. Using separate flashing and roof caulk works as good as anything and is the quickest/easiest. The cap shingles or top roof flashing over top would shed most of the water and hide the flashing/caulk anyway. I suppose you could bend the pan itself at the wall but that would take longer and adds an unnecessary level of difficulty. Or, maybe you know the "best" way, you didn't really say.The main purpose of the W is to slow and redirect/channel water so it doesn't wash back up the other side, thereby getting underneath the shingles or causing turbulence. This has been well proven and documented. The W has nothing to do with the pitches of the adjoining roofs. That doesn't even make sense.Clipping would be good way to go, not necessarily better or worse. I always nail, as long as the nails aren't too tight, there isn't any distortion. Nails are quicker, easier, cheaper, and give the same result.I must say though, if I had to bend it myself I would probably go with the V because it would be so much easier to bend. But since I can go to any roofing supply and buy a W in any color I need, I go that rout and have been very pleased.DC
The W has nothing to do with the pitches of the adjoining roofs. That doesn't even make sense.
I guess I didn't make myself clear.
If the roof plane on one side of the valley is steeper than the plane on the other side (ie, a 4/12 on one side and an 8/12 on the other) the potential for water crossing the center of the valley running from the steeper roof and encroaching on the lower pitched side is real. Otherwise, that "water will jump the center of the valley and run underneath the shingles on the other side" theory is just that - A theory. If your valley is installed properly it won't make any difference if it does. Also, on steep pitched roofs, I've seen the water "jump" over the other side of the valley to the opposite shingles after it hits the bump in the middle.
It's my experience that "W" valley tends to collect more debris than "V" valleys. With "W" valley, two smaller valleys are created, each with half the flow of a "V" valley in the same position. Consequently, there's less water volume to clean the valley.
The top is also an issue with "W", especially in cases like the OP's where it abutts a wall. With "V", I can make one cut and quickly solder it to have a long lasting, water tight, clean looking application.
I use both types of valley. I looked back over my records and so far this year, I've made about 1500 ft of valley. It's split about evenly between "V" and "W". Both have their applications. In the OP's case, I think "V" would serve him better. http://www.quittintime.com/ View Image
I must agree with most of what you just said and I understand now what you meant about pitches but I think it would be just as effective in same pitch situations until, like you said, it gets so steep there's nothing you can do.While the W has less flow, I would think it has less turbulent and therefore more efficient flow because the W directing the water. Even if so, the point is moot. I don't have extensive experience with copper pan, but would be nice to solder. I was speaking of aluminum pan which I flash, caulk and cover.The W does collect a negligible amount more debris, both collect a considerable amount less than a shingle valley.If the OP wants copper, I can agree he should use a V. If he uses aluminum I can't see it making a big difference for him either way but at least the differences are a bit less mystified for him now. DC
I would think it has less turbulent and therefore more efficient flow because the W directing the water. Even if so, the point is moot.
You're just making stuff up to justify your posistion. http://www.quittintime.com/ View Image
Just making stuff up? How dare you.I was pointing out how the W acted like a curb an gutter system rather than just allowing water to slosh about in an open pan. No need to make that up.DC
I was pointing out how the W acted like a curb an gutter system rather than just allowing water to slosh about in an open pan. No need to make that up.
The next time it rains, find a "V" valley and watch what happens. The water goes to the center and continues down hill. If you spray that valley with a water hose from one side, water may run across the center before it comes back to the middle as travels downward. But during rain, water is coming from both sides and it converges in the middle as it goes downhill. It doesn't slosh around. http://www.quittintime.com/ View Image
Seeyou has given a great response , so I won't need to go further.
Most real roofers don't use aluminum for valley flashings , and I'd never even consider a W in 99% of my work , but everyone has their own ways that they prefer.
real roofers don't use aluminum for valley flashings ,
Real roofers don't let fake roofers use aluminum for valley flashings or much of anything else on a roof. Hell, I won't even let my crew drink beer out of aluminum cans in my presence.http://www.quittintime.com/ View Image
Grant,
Just got the best laugh I've had in awhile looking at your beer can comment.
Must they use paper cups or long necked bottles ???
Must they use paper cups or long necked bottles ???
Long stemmed glasses with umbrellas and straws if I'm buyin', mister.http://www.quittintime.com/ View Image
be careful they don't drink too many of them, or they'll be catching dreams
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slatemani'm not sure I entirely understand what you described, but i do think its similar to what my foreman and I arrived at this afternoon. I will either send or pic or describe it later.thanks to all of you arthur
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