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3 tab long Island valleys


Chris Bernhardt
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I see this type of valley a lot in my area. I first learned about it in the Jan 2003 issue of Fine Homebuilding however the author said that this type of valley should only be made with laminated shingles.

Is this valley even when done with laminated shingles approved anywhere?

Is laying this type of valley using 3 tab shingles considered a defect?

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Chris, Oregon

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Properly done, the lower layer of shingles is lapped up under the upper layer to prevent water from getting below the roofing material. It is a common application. Googling Western Roof Council should get you diagrams of this valley type installed to manufacturer's specifictions.

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Hi,

Yes, cut valleys are quite common.

  • The upper watershed side should be the cut side with the lower watershed side continuing beneath the surface.
  • The layer of shingles lining the valley on the cut side should have been flipped around so that the tabs were beneath the upper-watershed shingles, leaving a long edge with 1/3 the number of potential trap points. That's rarely done because the other side of the shingle is a different color and the roofers don't want to answer the inevitable question about color differences.
  • The cut should be two inches back from the valley centerline and the upper corner of the upper watershed shingles - the corner that you can't see because it's concealed by the overlaps - should have been nipped off before application.
It looks like that cut line is directly down the centerline of the valley.

You can obtain a free manual and obtain free certification from Certainteed in their Master Shingle Applicator program by clicking here.

ONE TEAM - ONE FIGHT!!!

Mike

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Thanks for the replies such far however I would like to point your attention to the picture. Note this is not a closed cut valley. Look carefully and what you should see is that the valley was lined vertically with 3 tab shingles. This places the keyways horizontal and perpendicular to the valley which can direct and water under the shingle and hang up debris and obstruct flow.

In a closed cut valley the key ways will be roughly parallel, self draining and the overlapping valley is supposed to be cemented down.

The long island valley is touted as being the fastest way to make a valley because you don't have to cut anything but using a 3 tab strip shingle whose keyways are perpendicular and not self draining to the valley would appear to be poor practice.

In my googling around I haven't been able to find where this is an approved means of constructing a valley.

Mike, I acknowledge that you made comment on the fact that the 3 tab shingles lining the valley should have been flipped around and wasn't due to the color difference that would occur. Have you ever heard of a name for this type of valley? It resembles most closely a cut valley. The name the article applied to it was a long island valley. But I wonder how others refer to it?

Chris, Oregon

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Hi,

It's not a "Long-Island" valley. They might tend to call it that where you are, but it's actually what's known as an "Alternate Closed Cut" valley and it should have been done as I said, for the very reason that you pointed out - that the shingle tabs tend to capture debris.

It's done constantly here with architectural-grade shingles and, because those don't have tabs to capture debris and only the joints between shingles butted together at the ends, they typically don't flip them around and leave the laminated section abutting the valleys. However, when it's done with 3-tab, the shingle should be flipped so that the tabs aren't in the valley. I say should be because they usually are not, due to the color difference.

You're right, with a conventional closed-cut valley they're supposed to adhere the cut edge of the overlapping shingles in a 2-inch wide bed of goop. With an alternative closed cut valley where the tabs are facing the valley, gooping the corners down is certainly neater, but if the proper width underlayment has been used under that valley and there aren't any fasteners closer than 6 inches to the valley centerline, the likelihood of leakage is pretty remote without the goop. I know that, because I'm in a fairly rainy part of the country. We've had more than 14 inches so far in November this year (But, then again, I guess you are too). It's virtually never done here yet roofs seem to handle it well.

ONE TEAM - ONE FIGHT!!!

Mike

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Hi Chris,

I usually do comment about it when I find the tabs lining the valley and they haven't been gooped to prevent stuff that's sliding down the valley from building up underneath them.

It's easy to illustrate. One can usually slip a finger under an uplifted tab and pull out a bunch of pine needles, maple tree seeds and other flotsam.

However, at the same time I point out that I only rarely find them actually leaking and I'm careful to closely examine the underside of the valley from the attic, or the ceilings beneath when I can't get into an attic or there is no attic, for any signs of leakage due to improperly placed nails or improperly lapped underlayment, etc..

ONE TEAM - ONE FIGHT!!!

Mike

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Originally posted by Chris Bernhardt

I see this type of valley a lot in my area. I first learned about it in the Jan 2003 issue of Fine Homebuilding however the author said that this type of valley should only be made with laminated shingles.

Is this valley even when done with laminated shingles approved anywhere?

Yes. Look in the Certainteed Shingle Applicator's Manual (I have the 6th ed.). It's called an "alternate closed valley." Like the JLC author they say, "This application cannot be used with shingles that have cut-outs, such as a typical 3-tab strip shingle."

Is laying this type of valley using 3 tab shingles considered a defect?

Chris, Oregon

Perhaps. The Certainteed manual and the JLC article specifically say not to do it. However, I've been seeing it done with 3-tab shingles for the last 10 years or so and I have yet to see or hear of a leak that occured because of it.

It seems to me that, if you're willing to accept a butt joint perpendicular to the valley every three feet or so, then cutouts every foot or so shouldn't be a big deal. I don't see a functional difference.

Personally, I'd rather see three-tabs used in the Long Island configuration then see a conventionally constructed closed-cut valley with the points left intact.

Bottom line, on my own home I wouldn't mind if the roofer installed the shingles like this as long as he did everything else right.

- Jim Katen, Oregon

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The Certainteed manual and the JLC article specifically say not to do it. However, I've been seeing it done with 3-tab shingles for the last 10 years or so and I have yet to see or hear of a leak that occured because of it.

Well I'd probably agree. The trouble is all you need is one persnickety roofing contractor or other tradesperson to say its not right and strike the fear of God in the homeowner.

If that happens, there's nothing to fall back on.

I usually don't fall outside the specs of a manufacturer that are clearly printed.

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Hi Randy,

No worries. The quality of roof work around here is so bad that you'll never find a roofer that will ever criticize whether the tabs face the valley or face away from the valley. Believe me, I've argued with hundreds of them. Just about every one I've ever met had has head tucked so far up his bottom that he'd need to go to the proctologist to get his teeth capped.

OT - OF!!!

M.

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Originally posted by kurt

Yeah, finding roof defects is picking low hanging fruit. Observation......

If there's a valley liner, almost any combination of stupid roofing will still work. Anyone else poke around looking for valley liners? (It's not always possible to know for sure, but I look.)

Of course. While I'm there, I look for water between the liner and the underside of the shingles. That always makes for fun times.

- Jim Katen, Oregon

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