How to run shingles in a valley correctly

I am a framer by trade. I am building an addition to my house. I have a very gradual shed roof on the back of my house - maybe a 2 inch pitch. The addition is a standard a-frame roof w/ an 8 inch pitch. I have laid sleeper valleys on the shed roof for my rafters to die into. Once I have the plywood on, I know that i need to take a foot or two of the shingles off of the shed roof beside the new valley that I have created so I can roll out some valley paper down the valley. (I’m not a roofer so please tell me if this is incorrect) My number one question is, does the shingles from the steeper roof go under the more gradual one or visa versa? Or does it not matter either way? And second, Do i have to use the more expensive valley paper, or can I simply use a roll of thick felt paper down the valley?

buy some Ice and Water Guard/Gutter Guard and you may even want to run some valley tin. Run the lesser slope up onto the greater slope. Then when you shingle the greater slope, cut the greater slope shingles back a couple inches from the center of the valley. Make sure you dont have any nails in the valley or 6 inches or so back.

Well, you will have to remove about 2 feet worth of shingles, measuring from the center line of the valley. Then I would run a piece of ice and water shield straight down the valley. I would not use felt. Although I am sure that many do. Then replace the removed shingles on the lesser sloped roof and run those up onto the steeper roof. Making sure that they span across the valley and up the other roof by at least a foot. Do not nail within 6 inches of the valley. Then roof the other side of roof right over the other shingles. Notch each of these shingles at the top 2 inches at a 45 degree angle away from the valley, to help divert any water into the valley, and cut the valley.

Look @ the wrapper. It’s all there.

I would recommend hiring a professional to come and roof this small project. Sounds like there is a steeper roof running into a somewhat flat roof with a valley, if this is correct then some mistake will be made by a non professional roofer no matter how much info we all can provide on this forum. If a mistake is made in a valley, you will have alot more water issue in your house since the valley is where alot of water comes together. Hiring a professional will be cheaper in the long run. Sorry I couldnt provide any other info.

I woud use I&W and 24" W valley metal, like this- this is 12/12 into a 4/12,its 10yrs old now and NO problems.

Not to hijack. Kage, that’s a perfect example of the need for a channeled valley. W is completely wrong for that app. And one is as easy to make as the other.
This second valley is has a 2" cahnnel, 1" rib. They closed the ‘off’ side.

We have never had a problem in the 20 or so yrs i’ve been doing it that way,before that it was either closed valleys or the V valleys,…which suck,they made the W valley just for this reason…around here anyways,i think your valley there Tinner is good for SLATE but the other works just fine for archs…if done rite.

Don’t worry Kage. :slight_smile: I wasn’t picking on you. Just wanted to show a better way to do things. When I have mixed pitches, and have to have open valleys, I use the channel, shingles, cedar, or slate.
And it isn’t harder to make either. :slight_smile:

We’ve had some shingle roofs with 16/12 and 4/12. We just make the channel 3-4" wide. Rib can’t be jumped by water. A W is useless on those, and they should be closed, but different houses have different specs.
It’s just another tool in our arsenal, so to speak to make a ‘bulletproof’ roof.

BTW. I should have pointed out that the method is very dated, well back into the 1800’s. Just another method that hasn’t been improved upon yet. I didn’t come up with it.

I do those kind with some of the metal roofs i do,i forgot to mention. In the lower valley we used that kind your talkin…its a ph pic,but ya get the jist.Its a 12/12 comin into a 6 and then a 4… :mrgreen:

Oh yeah! I forgot that! Works great on metal too.
Some things come so naturally, like breathing, we don’t mention them. Often, I can’t even remember ‘why’ I do some things, but I know it’s right! :smiley:

Roofing is in the blood.