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cut valley


Phillip
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I think we have talked about this before and I haven't took the time to look it up.

From the ground it looks like a nice clean cut valley. When I get on the roof I find this.

Shingles that turn and run down the valley and then shingle run out on top of these shingles. No cut at all.

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Yeah, it's a California valley. The NRCA does not endorse it in areas that have heavy rains, snow or high winds. Don't you guys have two out of three of those things?

The shingle manufacturers that I'm familiar with don't list the installation in their valley construction methods guidelines.

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I like it. It makes a really nice tight line that looks good. Cut valleys end up leaving a fat black line that draws the eye, especially on lighter colored shingles, and looks irregular on highly dimensional architectural shingles. Then there's the cuts that end up less than straight. This is fast and easy, looks better, and works as well as a cut valley.

The only drawback is that the corners of the shingles lapping the valley course should be glued down with mastic, they won't seal themselves.

Tom

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Do any of you guys that support the installation have anything that says it's an approved method? I did some EW support for a client with this style valley on all eight valleys of his house and he ended up not having to pay the contractor because the shingle manufacturer stated, in writing, that the installation voided the warranty.

I've never had any issue with burying an electrical box in a wall but I still wouldn't do it. (often)

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I don't have any documentation to support my opinion but...

1. I've seen enough valleys with scabs, cut offs and otherwise improprly affixed pieces to know that it makes far better sense to work your way out of a valley (as this approach demands) than it does to work towards one (which is what happens most of the time).

2. Double cut valleys only appear when the materials demand them. Nobody does woven valleys because...well because roofers just aren't smart enough to weave them right, if they were they wouldn't be roofers. Closed cut valleys have become the norm, been that way for decades. If the industry can accept dumbing down the detail this far than the next logical step is to eliminate the cut altogether.

3. If the valley is properly built up with IWS and felt underlay, you'd have to try damned hard to make it leak, and with the extra layers of this (or the closed cut method) even more so.

4. Nobody reads directions anyway.

Tom

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That's used a lot around here.

In their master shingle applicator manual (Page 64) Certainteed calls that an "Alternate Closed Valley" application. Certainteed states in the manual that a closed valley is their preferred method of installation for all roofs except Custom Lok 25 and their Super Shangle products.

ONE TEAM - ONE FIGHT!!!

Mike

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Do any of you guys that support the installation have anything that says it's an approved method?

Mike beat me to the main one, but I have seen this valley detail shown by other manufacturers as well.

I did some EW support for a client with this style valley on all eight valleys of his house and he ended up not having to pay the contractor

Was the contractor given the option/ right to fix the valleys?

If I were to start writing this up as an issue on newer roofs, I would probably have to write up about 50% of them, including the last 2 I've inspected.

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Has I said I haven seen it before in my area and when you add these other details you wonder about the roof.

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and they did not replace this area

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1. I've seen enough valleys with scabs, cut offs and otherwise improprly affixed pieces to know that it makes far better sense to work your way out of a valley (as this approach demands) than it does to work towards one (which is what happens most of the time).

Except that approach negates the manufacturer's mandated course offsets.

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1. I've seen enough valleys with scabs, cut offs and otherwise improprly affixed pieces to know that it makes far better sense to work your way out of a valley (as this approach demands) than it does to work towards one (which is what happens most of the time).

Except that approach negates the manufacturer's mandated course offsets.

The one does not follow the other. If the angle of the valley is such that it doesn't produce the proper offset, you trim the first shingle in each course until you do have the correct offset, just as you would with a traditional closed cut valley. Only with this method, you trim them at 90 degrees.

Alternate closed-cut valleys have been standard practice around here for close to 15 years. Like any other valley method, if you do it properly, it works.

Certainteed includes it as an acceptable method.

Pabco grudgingly acknowledges it.

Malarkey doesn't argue with it.

That probably covers about 80% of the shingles I see.

Now maybe in places that get hard rain and strong winds this kind of valley sucks. But around here, it works just fine.

- Jim Katen, Oregon

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Now maybe in places that get hard rain and strong winds this kind of valley sucks. But around here, it works just fine.

- Jim Katen, Oregon

Nope, seems to work fine around here even in the hard driving rains; even when they don't bother to adhere the overlap with mastic - which is most of the time.

ONE TEAM - ONE FIGHT!!!

Mike

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you trim the first shingle in each course until you do have the correct offset, just as you would with a traditional closed cut valley. Only with this method, you trim them at 90 degrees.

To which I would say... Quit jerking around and trim them properly to 45 deg. [:)]

West Coast BC, up here on new housing we see open valleys mostly. painted metal valley flashing, so that says it, the woven valley has been tried.

Maybe OK where the rain is lightweight.

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See woven valleys here all the time too. We have as much rain as you do; maybe more. Open valleys, cut valleys, alternative closed cut valleys, it doesn't make a damn bit of difference. If the roof is done properly, it won't leak, if it isn't done properly it will leak, or it might leak, or it might go the entire life of the roof cover and never leak despite the fact that it's been done wrong. It all depends on what was done wrong.

You don't trim shingles at 45° with an alternate closed cut valley; you cut them at 90° and adjust the courses as you go so that they land where they are supposed to land and so the offsets will land where they are supposed to land. Do it right - leak free - do it wrong and it'll probably leak. It's the same with a woven valley, you have to plan each course and adjust so that you have proper offsets and so the portion of the shingle that lands on the valley will shed water - not collect it.

30+ years ago we used to lay out an entire course before setting a nail to it, study it and then adjust it left or right to get it exactly where we wanted it before we started nailing. Now they line up the offset on one shingle at the edge of the roof without even considering where they'll be by the time they get to the valleys and begin hammering away.

People don't learn this stuff anymore. It's out there in print (Roofers Handbook by Johnson, Roofing the Right Way by Bolt, etc.), but nobody really bothers to read it if they learned roofing from someone who learned it from someone who learned it from someone who learned to roof while working for a roofer for two weeks one summer 20 years ago and wasn't really paying attention.

ONE TEAM - ONE FIGHT!!!

Mike

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See woven valleys here all the time too. We have as much rain as you do; maybe more. Open valleys, cut valleys, alternative closed cut valleys, it doesn't make a damn bit of difference. If the roof is done properly, it won't leak, if it isn't done properly it will leak, or it might leak, or it might go the entire life of the roof cover and never leak despite the fact that it's been done wrong. It all depends on what was done wrong.

You don't trim shingles at 45° with an alternate closed cut valley; you cut them at 90° and adjust the courses as you go so that they land where they are supposed to land and so the offsets will land where they are supposed to land. Do it right - leak free - do it wrong and it'll probably leak. It's the same with a woven valley, you have to plan each course and adjust so that you have proper offsets and so the portion of the shingle that lands on the valley will shed water - not collect it.

30+ years ago we used to lay out an entire course before setting a nail to it, study it and then adjust it left or right to get it exactly where we wanted it before we started nailing. Now they line up the offset on one shingle at the edge of the roof without even considering where they'll be by the time they get to the valleys and begin hammering away.

People don't learn this stuff anymore. It's out there in print (Roofers Handbook by Johnson, Roofing the Right Way by Bolt, etc.), but nobody really bothers to read it if they learned roofing from someone who learned it from someone who learned it from someone who learned to roof while working for a roofer for two weeks one summer 20 years ago and wasn't really paying attention.

ONE TEAM - ONE FIGHT!!!

Mike

OK, I got what you were saying. I think they should either cut the shingles like a true cut valley, and make a better roof.

If they want to go without cutting as much, they could put in an open valley. Which is better, right?

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. . . Which is better, right? . . .

Define "better."

The people who see the alternate closed-cut method on a regular basis attest that it's no more likely to leak than the other methods. Given that any of the standard valley methods give leak-free performace, what criteria would you use to quantify "better?"

- Jim Katen, Oregon

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"Better" may mean the valley collects less debris or minimizes horizontal water migration or wears as well as the remainder of the roof or doesn't look like crap.

The "alternate" closed cut valley where Gary Blum lives in serious snow country won't work; all you see are open metal valleys narrow at the top, wide at the bottom.

Ice and water shield has bred a whole bunch of less than perfect practices.

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. . . Which is better, right? . . .

Define "better."

The people who see the alternate closed-cut method on a regular basis attest that it's no more likely to leak than the other methods. Given that any of the standard valley methods give leak-free performace, what criteria would you use to quantify "better?"

- Jim Katen, Oregon

Looks better. At least John K's picture does. I've never seen it like that before. Every alternate closed cut valley I've seen prior to that one is downright ugly. John's photo is appealing. That's would be the criteria, at least if it's my own house.

Marc

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I spoke with a field rep. with Malarkey today. He said that they don't approve of alternate valley installations. He said that while they won't void their warranty because of it, they would not write a letter saying that it was OK either.

I inspected a house a couple of weeks ago that was a flip. The newly installed roof was so bad that they had to rip it back off and replace it. The original roofer was not given the option to re- do it, and a new roofer was called in to install another new roof.

I re- inspected the newest new roof and had a few issues with the installation. The roofer decided to play hardball, and stated that they didn't have to fix anything I had written up-- bad choice.

In my report, I'd written that while the valley detail was not specifically mentioned in Malarkey's installation instructions, it was a common practice. I mentioned that all of their valley details indicate the need for sealant.

The roofer refused to seal the shingles down on the grounds that this may cause leakage. I told the field rep. this, and he flatly stated "if they're worried about leakage, they need to tear the valleys back off and do them according to our manual"[:-thumbu] I'm so used to field reps being wishy washy, that I was flabbergasted.

Based on the rep's reply, I would have to say that Malarkey is on the no go side of things for this type of detail.

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