# Metal roofing installed incorrectly



## milz45 (Jul 7, 2012)

Hi,
I've got a place in WV I've been rehabbing for 2 years now. We knew the metal master rib roof had several leaks when we bought. First thing we did was have our GC replace the screws which were in rough shape. Long story short, we still have a few leak points. I got up on the roof this weekend and I believe I know what the issue might be. It appears that whoever put this roof on got the the overlap and underlap reserved. Doing a little reading it seems (no pun intended) that when this happens, water can be pulled up into and over the bottom rib, making it's way to the sheathing. I'm wondering what my options are here. I cannot afford to put a new roof on this house. The panels are in good shape. Should pull the screws at the seams and try to correct the overlap/underlap at each seam? I'm concerned that the way they are stacked, they might not lay in a good position when I reverse them. Maybe it would be fine. There are also some boots that I'd need to tear off and fix. I've seen some products that have a membrane and coating for seams. That would certainly be easier, but don't know if that would resolve the issue either. Any thoughts?
Thanks!
milz45


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## Chris616 (Dec 31, 2019)

Assuming that you intended to type “reversed” instead of “reserved”, what do you mean by “got the overlap and underlap reversed”?

Your photo shows one possible leak point. The screw in the centre of the photo has a gasket preventing water getting in where the green arrow is, but nothing to seal the hole underneath, so water entering where the red arrow is can make its way through. The screw should have been on the other side of the "peak".

Chris










Like shown in the instructions:


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## Randy Bush (Dec 9, 2020)

Chris616 said:


> Assuming that you intended to type “reversed” instead of “reserved”, what do you mean by “got the overlap and underlap reversed”?
> 
> Your photo shows one possible leak point. The screw in the centre of the photo has a gasket preventing water getting in where the green arrow is, but nothing to seal the hole underneath, so water entering where the red arrow is can make its way through. The screw should have been on the other side of the "peak".
> 
> ...


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## oggy bleacher (May 3, 2011)

Hard to tell from that photo. What sq ft of roof. What pitch? Its Possible to add butyl tape without tearing the whole thing off. The placement of that screw is now a leak spot even if the washer is sound the water will run under the seam and down the screw. That will be hard to fix. How many screws are on the wrong side of the rib like that? Those have to be remedied. The screw ON the rib is probably a stitch screw. Find the fastening pattern you think is right and change what you can. Tex_rib #1 looks right or the metal sales.
Gutter sealant can fill empty holes if you clean the metal good.


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## BigJim (Sep 2, 2008)

Is the metal roof installed over plywood or another roof of some sort? If the metal roof is installed on just 2Xs, the leak may be from condensation instead of an actual leak.


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## milz45 (Jul 7, 2012)

Yes, I meant to say "reversed." The overlap is actually the underlap as @Randy Bush pointed out.
@oggy bleacher the pitch goes from about a 4/14 to a 7/12. It's about probably about 2700 sq ft. Thanks for pointing out that screw placement. From my pictures, it does look like there are a handful on most seems, although not all.
@BigJim the roof is installed over plywood, and there's a thermal break of foam as well. So I don't think it's condensation. And I definitely get my drips when it's raining.

So based on the feedback, I should remove those remove the screws on the wrong side of the seam and seal the holes. With the screw gone, I will need to seal the bottom hole to stop the water from getting in. 

My other question, is whether just having the overlap/underlap reversed, will that enable water to get in as well? I'm trying to determine if I should try to correct the seams as best I can, or somehow seal them off. Any experience out there fixing this particular issue?


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## Chris616 (Dec 31, 2019)

Randy Bush’s comments have disappeared, but I understand now from the drawing what you mean by reversed. The short horizontal extension (red arrow on drawing below) should only exist on the piece underneath. 

I suspect that the biggest benefit of installing in the proper order is that it makes it impossible for the installer to create leak points like shown in your photo by driving a screw through that short horizontal piece. The manufacturer does mention the gap that putting the pieces in the correct order produces and which helps to prevent water wicking up between the two pieces (see diagram below). How much, if any, water actually does that? Tough to know.

You’ll get differing opinions on what, if anything, to do about this. I suspect that correcting the problem with the incorrectly placed screws will solve any visible leaks. You might still get some water migrating between the pieces via capillary action, ending up on the plywood and very slowly causing rot. If it were me. I’d undo one seam and understand:

Is there any sign of water migrating between the two sheets and getting to the plywood, and;
How difficult it would be to lift the two pieces up and lay them back down in the right order, and;
Whether they would lay down on top of each other properly or if there is now a slight misalignment, meaning that to do this properly would require stripping the roof.
Chris


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## Randy Bush (Dec 9, 2020)

Well now that is weird my comments disappeared. The flatered the roof the more chances of wicking . It's possible to put the panels back correctly. will just take time. With 4 1/2 and better there is no need for stitch screws, but if you have screws ther now that hole has to have a screw in it.


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## oggy bleacher (May 3, 2011)

2700 sq ft. Are all the panels overlapped wrong? If the top edge under the ridge cap is turned up then it would have to be flattened if you flipped the panel 180 degrees. And then the bottom would have cuts. But that rib style doesnt look like a panel that gets turned up.
Yeah, take those seam screws out, fill the bottom hole after cleaning the metal then put the screw on the other side of the panel where it belongs. You could lay some butyl tape under the rib if you remove the stitch screws. But I would guess the leak is from the screws , not from wicking over the rib.


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## milz45 (Jul 7, 2012)

@Chris616 Thank you. That approach seems very prudent to me. I think I'll pop off the ridge and then undo a seam to learn a little more. The best fix would be to put the overlap the way it's intended, but I'm not sure how difficult that will be. I will have to remove a few boots, including a brand new one that was added for the wood stove stack. It'll be a pain, but I'll have a look to see if it's doable without pulling the whole roof off. I will also remedy the incorrect screws.

If that doesn't work, maybe I'll look at using seam tape? I don't really like that idea, as it seems very much like a band-aid, but maybe that would get me buy for several more years. Not sure.

@Randy Bush Thanks. I can still see your comment. I just had to click "view more" on your old post and it shows up at the bottom.


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## oggy bleacher (May 3, 2011)

Butyl tape is part of the installation for some.brands.and for lower pitch roof. It may already be under that seam. If so then the leak is from the screw.


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## Randy Bush (Dec 9, 2020)

It would nice to see a picture stepped back some.


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## milz45 (Jul 7, 2012)

Thanks, everyone. I will head out not this weekend but next. I'll get some pics of what I find and report back.


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## milz45 (Jul 7, 2012)

Here's the only other pic I grabbed when I was there last. It shows a new boot I had added to the wood stove stack.


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## Randy Bush (Dec 9, 2020)

Wow it is no wonder your roof leaks. From what I can see , it looks like a lot of the screws are in at an angle and not properly seated. Also it is not correct to put the screw in the middle between the ribs.


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## Windows on Wash (Aug 30, 2011)

Randy Bush said:


> Wow it is no wonder your roof leaks. From what I can see , it looks like a lot of the screws are in at an angle and not properly seated. Also it is not correct to put the screw in the middle between the ribs.


This is all you need...


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## milz45 (Jul 7, 2012)

I wanted to follow back up on this one. It does appear that the primary leak point are coming from either the screws at the seams where they've been overlapped incorrectly as @Randy Bush pointed out, or from crocked or inadequately seated screws. What I did was a mix of things. I've tried to pull up and correct the overlap on a portion of the roof. However, without removing all screws from the entire panel, the stack-up at the seam starts to add up over about 4 panels and the seams don't lay very well. For other seams, I left them "as is" but opened them up so I could get a good bead of tube butyl down the length. Then reseated the seam with new screws. I've basically replaced all the screws in the trouble spots. We've had one rain and I've not seen any signs of leakage. I will most likely replace all screws on the roof over time for piece of mind. Thanks for everyone's help. Fingers crossed that we're water tight for years to come.


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## Chris616 (Dec 31, 2019)

Thanks for letting us know the resolution.

Chris


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## Randy Bush (Dec 9, 2020)

Glad it is working out so far for you. 

Sent from my SM-A115A using Tapatalk


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## tstex (Nov 14, 2014)

I've installed 6 metal roofs at my ranch w R-Panels 26ga Galvalum. Never had a leak...

there are 2 types of screws for metal roofs: Longer screws that secure the metal sheets to the wood underpinning, and shorter screws that secure metal to metal on the connecting seams/ribs...butyl tape goes btw the seams, then the smaller screws, b-tape and the sun seals the seams. 

My question, when you bought this place, was it subject to an inspection? Rural areas maybe not, but if so, that should have been caught. 

Due to budgets, I know you had to make this work...but, the next windfall you receive, think about replacing the roof and using the old sheets for other projects. You can seal the holes w tar roofing material from underneath, then make siding out of it for older sheds or roofing on new projects. When you sell this place, any astute buyer is going to see it was installed completely wrong. With sun, wind, rain, large temperature swings and debris being caught under the long side of the incorrectly installed joints/seams, it will start to eventually leak again...good luck


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## Octane (Feb 13, 2021)

Glad it's working for you.My way would have been to raise the seams lay a bead of caulk the full length of panel on the top of the overlap and put the screws back in as is.


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## awazhoona (Jul 31, 2021)

tstex said:


> I've installed 6 metal roofs at my ranch w R-Panels 26ga Galvalum. Never had a leak...
> 
> there are 2 types of screws for metal roofs: Longer screws that secure the metal sheets to the wood underpinning, and shorter screws that secure metal to metal on the connecting seams/ribs...butyl tape goes btw the seams, then the smaller screws, b-tape and the sun seals the seams.
> 
> ...


That's really a good setup indeed.


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