# Need input on this open valley technique



## violin (Oct 19, 2009)

When I researched various "valley methods" a year ago, I came across the method you mentioned on the Internet web site. This method will work only for one-piece laminated shingles. I decided to use "woven valley" method as shown in the thread: Ridge Vent by shortedged. The woven valley has 4 layers of shingles instead of 2. I work from the valley using full size shingles and then toward left and then right.

In your method, you can lay shingles on one side, say left side, and cover the valley and into the right side by about 12". When the left side is completed, you lay the "valley shingles" straight up and then work on the right side. The tricky point is you should avoid butt joint in the valley.

Laminated shingles are more difficult to cut, therefore no-cut valley is an advantage. DIY roofing is not a rocket science, but a hard work. Since I worked by myself using a hammer, I removed a small area of old shingles which I could replace it in one weekend. Then I put a row of shingles under the old one to cover the border area and wait till next weekend. After I gained the experience, I decide to re-roof my cabin north of Minnesota border next spring. I bought a coil roofing nailer made by Kyson Tool in Texas, a roll of 1/4" by 50' polyurethane hose (remember to Buy American), and a used compressor from the local kijiji site. The compressor runs at 1700 rpm and very quiet.


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## ArmchairDIY (Oct 21, 2009)

jogr said:


> A 22 year old family friend has offered to help me reroof my house. He's worked for a roofing outfit for a couple summers so he has pretty good experience. He suggested a technique for the valleys that one of the "oldtimers" taught him. I'd like your opinion on it as I have never seen it before.
> 
> We are doing open valleys with w metal flashing. Shingles are Timberline 30 yr HD laminates. I&W at eaves and in the valleys. 4/12 roof pitch. Rather than run the shingles into the valley, pop a chalk line and cut them off (as per the GAF directions) he is suggesting the following:
> 
> ...


If I understand your description correctly, my answer is NO, don't do it. 
It sound like a bad idea to me. Stick with the manufactured suggested methods. It is difficult at best to get a shingle manufacture to warranty a product as it is. Don't deviate from their approved methods. Saving a few cuts in trade for doing a job correctly is never a good choice.


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## violin (Oct 19, 2009)

Go to this web site:
http://www.toolsofthetrade.net/industry-news.asp?sectionID=1537&articleID=501452


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## jogr (Jul 24, 2007)

That link looks like a closed valley variation of what he's describing. I've decided against closed valley in part because I actually like the open flashing look better (though I know many say the closed looks better) and in part because IKO has warned about reduced shingle life on closed valleys for 4/12 roofs and recommends open valleys for 4/12 roofs. They say that the even lower slope of the valley (2.8/12) results in faster wear on the valley shingles. I'm not using IKO shingles but the same should apply to all brands of shingles.

Unless I hear from some pros on here that the no-cut open valley method is as good as the cut method then as Armchair stated I'm going with the cut method described by the manufacturer.

Those laminated shingles don't cut as easily at 50 degrees. Any body got a tip on a tool or technique for quick, straight, clean cuts in cool weather? I've heard some folks use tin snips?


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## Filbee (Oct 17, 2009)

You probably shouldn't worry about premature shingle wear specifically in your valleys. Shingles (even if designated to be 25 or 30 year) don't ever live up to their descriptions. However, the method proposed by your friend is a cheaper way of gaining the aesthetic found in performing the work properly. The problem is, as you mentioned, that the sidelap of the shingles is only about 4-5 inches in most places and that the rows of dimensional shingles should follow a specific starting pattern so that you can't see the sequentially staggered courses of shingles all the way up the roof.


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## violin (Oct 19, 2009)

Sorry jogr, I didn't read carefully that you wanted open valley.


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## Slyfox (Jun 13, 2008)

The step off pattern shown by the manufacturer "in most cases" is just the recommended pattern to help less experienced roofers break up the stagger,
that doe's not mean it's the only way you can run them.

If you use the method "tamko valley' you can still break up the stagger by installing a half shingle on every fourth or fifth course.
9----
8----------
7---------
6--------
5----
4----------
3---------
2--------
1-------

As far as rather or not a 30 year shingle will last it's expected life span,
I have installed hundreds of roofs that have.
It's all about the quality of workmanship used during installation.
The first 30 year timberline I ever installed was in 1984 and that roof is still intact and holding out water to this day.


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## eisert (Oct 20, 2009)

I am a professional carpenter, and have roofed well over 1000 homes. I know exactly what you are talking about and have done it hundreds of times myself. If done correctly, it is an extremely reliable valley system, even more so than running the shingles long and the cutting to a chalk line. Go ahead with it. If anyone wants to know why this is such a good system, I will explain it, but the explaination will be extremely lengthly.


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## violin (Oct 19, 2009)

eisert, please explain it. If you have pictures or diagram to show us would be even better. I don't understand what jogr mentioned: "Run a single line of shingles up the valley with the bottom 39" edge of the shingle parallel with the flashing "v" and located to form the edge that would normally be created by popping the chalk line and cutting the shingles". The metal flashing selling at the local HomeDepot is only 18" wide.


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## Dale Chomechko (Mar 11, 2008)

No Problem! It's called a California style valley. It has been used for years & does appear on some instruction. If you look at the coverage & the fact laying them parallel with the valley lets all the joints face down without any cut "points" in the valley, it makes a better installation. We actually get it specified by consultants.
Dale Chomechko
DC Roofing Inc


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## crackdaddy (Oct 28, 2011)

Check this out, I think this may help a bit. 

http://www.youtube.com/watch?v=oqGqfTgg3d4


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## seeyou (Dec 12, 2008)

Most manufactures allow this method with laminate shingles. We often use it, but you still must cut the shingles to length to get the proper stagger between butt joints on steeper pitches.


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