To weave or to half cut? That is the question


What do experienced roofers generally prefer? Weaving a valley? Or doing a California cut on a valley?

I ask because of waste. I haven’t seen cutting a valley in 15 years, now all of a sudden it is back in style. I want to know who prefers what and why. Pkease don’t say waste is less by cutting. Quality is more important.



Closed cut or open cut are what is “recommended” on most architectural shingles. Some only allow for open cut. Closed cut or “California” cut 2" from center line with ice and water is best. Less lift, curling, and reduced likelihood of bridging in valley. Also aesthetically more pleasing to most as it creates well defined lines.


Oh yeah…less waste too!:stuck_out_tongue_winking_eye:


Most roofs being installed these days are arch shingles. As far as I know there isn’t a single manufacturer who allows them to be weaved. Yes, it “can” be done but it isn’t “by the book”. With that said, I almost always do a California cut and my 2nd choice is a closed cut.


Open w metal valley is what we recommend and prefer. Closed or California valley use more shingles which mostly negates the cost of the metal. IMHO


I agree but there is more labor involved in doing open metal valleys, at least the way I do it there is.

People like the California valley because it is faster and doesn’t require as much cutting, it’s the least desirable way to do a valley and I wish the manufacturers would say so.

This is the same reason guys like the roll vent, it can be applied with a nail gun.

They really do not care that the roll vent has 40% less free area they just care that it is faster.

IMO companies with this philosophy should be disregarded since their choice of material and methods are inferior and they care more about getting it done fast than doing a good job.


Totally agree, should be focusing on quality and code standards. Even if the codes aren’t being enforced, we should hold ourselves to a higher standard for our sake and our customers sake.


ARMA standards …no weave, lace with laminate shingles.


I personally prefer the closed cut valley. Only one side open. We always position our valley adjacent joint lines over the peel too. Had this convo with OC years ago. You “can” rack arches and you “can” lace most 30 yr. It is not recommended but won’t void mnfg warranty. I also don’t know any reputable company in my area that laces archs…for the reasons I stated above.


I can only think of 3 times recently where I have seen woven valleys, 2 were arch, one was grand manors. All 3 looked horrible. We give 2 options closed cut standard, or open copper at a linear ft up charge.

With all high end shingles, grand manor, Camelot, carriage, we will only do open copper valleys and full copper pipe boots, if they want closed valleys they can find another contractor.


I’d love to see a picture of a woven Grand Manor valley.


It was a dormer, exposures didn’t line up evenly, it was the biggest waste of expensive shingles I had ever seen. Custom hired a family friend who said he was a roofer to do it.


GAF will void a warranty if woven, when youre installing a golden pledge roof.


Did not know that. We dont install very much GAF. Certainteed, Tamko, and Atlas