Which roofing method is better?

[braumeister]

Looking to replace the roof (it's 19 years old) and wondering about the technique.

Currently, there is a metal strip in the "valleys" where one eave meets another. One company wants to simply replace that.
The other company would be happy to do that too, but says it's an older technique and their newer "weaving" technique is better. It's also cheaper.

I know very little about roofing, but I'm sure there are members here who do.

What do you think?

 

[samclem]

The weaving is generally termed a "California Valley." It is now by far the most popular way of handling a valley. It does save on material and labor.

I don't honestly know which is better. It seems to me that the use of the " W " flashing is more likely to prevent water from flowing across the valley and getting under/forcing up the shingles under the other side. Shingles are designed to shed water directly down, (perpendicular to the long edge), and when water comes at them from the side it can lead to problems. But, a roofer I respect told me there's no difference in performance between the two valley types. At any rate, getting the flashing is likely going to cost more.

Getting a good stick-down underlayment ("Ice and water shield") in the valleys and the eaves/rake edges is important no matter which way you go.

 

[Scrapr]

Are you stripping the whole roof? The "newer" technique is to put Ice & water shield in at least the valleys & eaves. In Bend it is required to I&W the entire roof. I&W is a sticky membrane that will seal up around nail/staple holes as you drive them.

Weaving was used in the 70's and probably before. i'm not a big fan of it. Maybe my technique was bad but it's easy to get a hump in the valley. You "might" be able to reuse the metal. Take a look at it. Safer to get new metal

I might let them weave it if I&W was done first. But i'm kinda a old school guy and would use the metal system. Sounds like the weaver was trying to undercut the traditionalist. But the sales fluff about weaving being a new technique is wrong

 

[braumeister]

Yes, the ice and water shield is installed first, so that's not an issue.

 

[pb4uski]

FWIW our house which was built in 2011 was weave... we never had a discussion on it with the builder.... and we have never had a problem.

Since I&W Shield has come down in price, around here some roofers just I&W Shield the whole roof and then put down shingles.... we did this on 3 of 4 buildings... the earlier one just did I&W Shield on the edges and the valleys.

 

[foxfirev5]

Plenty of roofs here. As a matter of fact I'm trying to facilitate DM's roof from 500 miles away. Dealing with crooks in the NE is not pleasant after retiring here in the Midwest. But I digress.

Both work fine. The only red flag I would have would be the contractor using the weave method. Not the process but the fact that he states that it's new. However the true weave required considerable skill and did not have the cut line down the valley. (Old school)

By stating that its a new process makes me wonder what experience level we're dealing with.

 

[braumeister]

By stating that its a new process makes me wonder what experience level we're dealing with.

Thank you. I should correct my comment and say that he didn't call it new, he just said they didn't do many metal strip valleys any more, mostly the weave.

 

[Walt34]

When we got a new roof on the old house near D.C. the roofer did the weave and we didn't have any leaks with it. But we were only there for about three years afterward so that may not mean much.

 

[eytonxav]

I was under the impression that metal valleys are always installed whether a weave is used or not. If not, I would certainly specify the installation of a metal valley layer beneath the shingles regardless of how the shingles are installed.

 

[RE2Boys]

I had my roof re-done 11 years ago hear in PA, where we deal with lots of snow and ice dams can be a problem. My roof valleys are done with the weave technique and we have ahd no problems with leaks from the valleys. Of course, I insisted on liberal use of the Ice & Water shield in the valleys and bottom six feet near the gutter.

 

[Badger]

I like metal enough to have my whole roof done in standing seam. No leaks and doesnt rip or get sun rot and loosen up. It has stood up well in hot summer sun and hurricanes.



Cheers!

 

[ncbill]

Improper flashing has given us the most trouble at my development (been on the HOA board for years) when we have had buildings (3-4 units/building) re-roofed.