Standing seam valley design

Please show me more IslandRoofing.
I want to learn. More pics if possible please.
How it snaps in.
I would love to do this if it works.
I might actually start supporting more metal roofs installations.

Standard standing seam installation is the only system I have felt comfortable with and it just takes me too long to make a good profit.
Any way i can save time and scratches and cuts sounds dreamy.

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You’re lucky rooflover, i’m Working on one now. Will take some for you!

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I met with the roofer and a couple of installers today. They brought a mock-up of the design used on my roof. (photos attached) Their rationale for the design they used is that the screws in the z flashing where the panel is wrapped would get alot of pressure, become loose and eventually leak. The owner of the roofing company is a standup guy from all indications and wants to keep me satisfied. He has offered to have an engineer look at the design mock-up and have them certify it. I’d like to ask you folks to take a look at their mock-up and give me your thoughts.

The one on the right is what they used on my roof(probably obvious). The one on the left seems to be what most standing seam roofers use.

Yeah, that’s a terrible and lazy way to do it. I also call b.s. about their rationale, they did it that was as it’s half the work.


We do a fair bit of SS and i have never seen that detail they are trying to rationalize. One look at your completed roof tells you that is wrong. It doesn’t loot good, traps debris, not a manufacturer approved detail. I cant believe someone who does SS would do that, appears to be more like there B team with little exp or a training crew with no supervision.

Glad to hear the owner is willing to work correct it.

I didn’t want to comment again because I felt it was frivolous. After seeing roof lovers blood type I had to pipe in. Dang it roof lover! I normally only show my smashed, bleeding thumbs, forearms, wrist and bloody knife to my wife, but dang. Put some methylade on that sucker. You may be to young for that. It turned your skin orange for a month. Burned like heck. Monkey blood.
As for the detail. I use the offset cleat, like on the left picture. This forces water into the valley.
The way it is now, the valley has no purpose. The water shed isn’t into the valley. Your leak protection all comes down to the turn back on the valley.
I don’t understand the concept, but I’m not left handed nor do I eat liver. It’s just weird.

Liver is pretty good! You ought to try it cooked a bit…

The one on the right is relying on a strip of sealant, which should be butyl tape, not sure what that mess on the mockup is, to top water once that thin J channel fills up. The only water that will actually get in the valley is when the rain is heavy enough to completely fill the J channel.

Butyl sealant only works under compression, that is why end laps and z closures are usually fastened every 2 inches to get uniform compression. As it is the ends of the panels are not fastened in the valley or turned over. There will be no compression to seal against their sealant strip.

They are not showing any additional fasteners in that J-channel and it recesses in the valley metal turn up on the side. So what is holding the valley metal in place? What is holding that J channel in place?

If it is fastened in place it will leak since the J channel will fill with water and your roof is low enough slope that the water will run up the inside under the panel and when the sealant fails it will run up to the lip then under the j channel. When it comes down it will either get trapped if they are using some kind of adhesive to hold the j channel in place, or run over screws and cause a leak.

If there are no screws then the valley metal is only being held by the sealants they used to glue the pieces together, eventually the whole valley might slide down exposing the top.

In a heavy enough rain the valley could fill and water would either go back under the J-channel to any fasteners, or the j channel and valley could fill and go over the lip in the valley metal. Then your ice and water will be the only thing stopping a leak.

If there are no fasteners under the J-channel then the entire valley is relying solely on the bottom panel fasteners to resist wind uplift. Valley can experience significant uplift since a strong wind will be funneled up the valley.

The detail on the left is actually done wrong. As mentioned the fasteners in the Z closure should be every 2 inches, or at most every 4 inches to ensure compression. The valley is fastened so it can’t move and the panel will be turned over and hooked to the Z, and ideally a bead of sealant or rope caulk will be put on the top of the Z before the panel is turned over, mainly as a fail safe if for some reason water or snow can build up that high.

There are other details like the Berridge one that do not use sealants in valleys, which IMO are superior to using a Z in a valley. Some manufacturers make their valley so it has a flange or even tabs that come off the side to be fastened up higher than the panel where it is turned over and hooked into the valley metal. Some details also fasten the panel ends in the valleys.

I would not accept that detail on a project.

Thanks to all for your comments and advice. The latest discussion with my roofer is that they are going to have Haag Engineering review their mock-up and try to get it certified by an engineering firm. I think that is wise on their part because of potential future liability and risk of loss of business due to the non standard detail. Surprisingly, it appears that I am the first person that has challenged the design. I’ll report back on the results of the Haag tests and engineering certification once I hear from my contact with the roofing co. Thanks again for your willingness to share your expertise.

The engineering firm came back with a review of the pros and cons of both installations. My interpretation is that they very politely said that the industry standard fold and pull valley design is the best way. The roofing company has agreed to redo the valley and pitch transition details. I really hate that this is going to cost them a lot of money, not to mention that it is going to be disruptive to me. This company and the owner are a well respected local firm and I want them to be successful. I hope this has convinced them to abandon the “east Texas” installation details and use the most common and accepted version. Thanks to all of you for your help with this.


Thanks for the update and clarification. I’ve only done ag and commercial metal, but that detail didn’t look like it would work at all!

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Well, you have your answer to your concerns. I’ve been on 1000’s of roofs in Southeast Texas. I’ve never seen a metal roof installed like that. Their east Texas install, must be so far north and east, they are standing in the Sabine River.
Your concerns were legit. Don’t feel bad. Every contractor out there should be striving for better, finished projects. Very few do I finish that I don’t find something that could have been done faster or better.


Before and after pictures. Much better!

This is a picture of the ends of the panels that they took off. I have to believe that it was only a matter of time before all of that muck that collected in the “leaf and dirt catcher” would have caused corrosion, let alone a nasty buildup that was visible to the naked eye. Thank you to all who commented on the design.

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Polar59. Are you available to chat? I had a metal roof installed last summer. Same problem. Hope your still monitoring messages. Can I share my number and email on this forum? Kathy

Polar59. I hope you come back to this forum. I wish to get advice from you about the same issue. My roof was installed summer 2021. Valleys plus most everything else is wrong.

If you have the same valley detail as the op it is done wrong.
The issue you will have is getting the contractor back to fix it after a year, i assume you paid them in full.

My concern: any good roofing company wouldn’t do that valley detail so your dealing with folks that don’t really know standing seam or who subbed it to a hack. The before valley and after valley pics posted by the OP at the end clearly shows the issue with the original valley detail.

Thanks Andy. That is what many have said.