Woven 3 tab valley, pitches not equal

I have to re-shingle a valley in North Carolina. It had metal flashing, rusted with some rusted through holes lower down, with ants and damp felt underneath and on top too (under shingles). The metal was not pressed into a “V” but was curved. The valley shingles were woven, with many single tabs in the valley (despite all this, sheathing boards in the valley are still fine).

So far I have only stripped this valley 3/4 up, from there to the ridge it is intact and I haven’t decided whether to strip the rest.

The gable side of the valley has a steeper pitch than the eave side, so if woven, the 3 tab shingles would not meet one on one, ratio appears to be 5 on steeper roof would meet 6 on less steep roof. Is it even possible to weave this valley?

Strip the whole valley. If you just pay attention where the center of the valley is, the shingles will tell you where to cross pitches. Closest shingle butt should be no more than 18" from the centerline. Weaving 3 tabs isn’t a good idea IMO.

Why would you want to weave it? Install IWS as a valley lining instead of valley metal and use a closed cut, half laced valley install. Way less trim waste and easier to do correctly. And since so many roofers don’t really do a good job with woven valleys, I think the closed cut, half laced looks better as well. That of course involves personal taste.

thanks for the replies. I am using IWS. I’m leaning towards stripping to ridge and doing closed cut. The one thing I like though about the woven valleys on this house, is that they are tolerant of powerful leaf blowers being pointed the wrong way.image|375x500

The pitch isn’t that much different. Run the low side through and cut the high side an inch or so out of the waterway. Once it seals down leaf blower shouldn’t be an issue.

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Weaving it is fine if you want to match the rest of the house or whatnot – when you have two different pitches you just need to double up on one side every so often. (ie. lay two in a row from the opposite side when the point where your shingles meet starts to be too far out of the actual valley) Definitely strip the whole thing though, not worth it trying to tie in from the bottom.