Steel roof leaking

[s219]

I've only put on 3 metal roofs in my life, but learned a lot each time and did a lot of homework before that very first job.

Most common leaks are due to people over-driving the screws so that the screw gasket squishes and bulges out, then it's exposed to the elements and deteriorates much faster. The gasket should just barely plump then you stop screwing down. This way the washer acts as a "hat" to protect the gasket underneath.

The second issue is lack of use of butyl tape at the overlap seams. Seems like it should be common knowledge or a requirement, but many people skip the tape. Many people also fail to orient the overlaps away from the prevailing wind, making that problem even worse! If you orient the overlaps and use tape, those seams should never leak. Tape should also be used where any gable trim screws down over the top of the edge panels.

Finally, ridge lines are often handled wrong. There should be a foam gasket in place to seal the gaps in the corrugation. Butyl tape should go down on top of the gasket, and then the ridge cap screws down over that through the raised part of the corrugations. I like using self tapping metal screws to screw the ridge cap to the panels. If you use longer wood screws to screw the cap through the panels into purlins or sheathing, you get less control over snugging everything together without over-driving the screws, but it's doable.

So in this case, I'd climb up on the roof and take a look at the screws/washers/gaskets, the panel seams (look for tape or lack of it by trying to slide an index card through), and then eyeball the ridge cap and seals.

Issues at the ridge will tend to leak right at the ridge in most cases. Seam leaks and screw leaks can appear to be widespread or present drips in places away from the actual leak. In general, leaks are a pain to diagnose, but try to keep looking for the farthest "uphill" place where you see the water and start from there with diagnosis/repair.

 

[mcgoo]

I've only put on 3 metal roofs in my life, but learned a lot each time and did a lot of homework before that very first job.

Most common leaks are due to people over-driving the screws so that the screw gasket squishes and bulges out, then it's exposed to the elements and deteriorates much faster. The gasket should just barely plump then you stop screwing down. This way the washer acts as a "hat" to protect the gasket underneath.

The second issue is lack of use of butyl tape at the overlap seams. Seems like it should be common knowledge or a requirement, but many people skip the tape. Many people also fail to orient the overlaps away from the prevailing wind, making that problem even worse! If you orient the overlaps and use tape, those seams should never leak. Tape should also be used where any gable trim screws down over the top of the edge panels.

Finally, ridge lines are often handled wrong. There should be a foam gasket in place to seal the gaps in the corrugation. Butyl tape should go down on top of the gasket, and then the ridge cap screws down over that through the raised part of the corrugations. I like using self tapping metal screws to screw the ridge cap to the panels. If you use longer wood screws to screw the cap through the panels into purlins or sheathing, you get less control over snugging everything together without over-driving the screws, but it's doable.

So in this case, I'd climb up on the roof and take a look at the screws/washers/gaskets, the panel seams (look for tape or lack of it by trying to slide an index card through), and then eyeball the ridge cap and seals.

Issues at the ridge will tend to leak right at the ridge in most cases. Seam leaks and screw leaks can appear to be widespread or present drips in places away from the actual leak. In general, leaks are a pain to diagnose, but try to keep looking for the farthest "uphill" place where you see the water and start from there with diagnosis/repair.

Okay thanks for the advice. The roof has no tape in between the seams it's just bare metal. We read it all the screws as the old ones are rusted in the seals were gone. It's possible we over tighten some of them. I would have to get up and look at them again.

 

[PILOON]

A lot depends on roof pitch as well, A low pitch will allow more seepage where the sheets overlap.
Conversely on a very steep pitch the rain picks up speed and will infiltrate especially intersecting roof elements as we see on many modern houses.
Then comes a very low pitch that gets a snow load and the weight pulls the seems apart allowing infiltration.
In colder climates you also get ice dams that let water back up and again problems.

On the positive side I have seen metal roofs on homes that have proper ventilation and good vapor barrier that will last forever.
But also saw bad jobs that the insulation was so waterlogged that it surprised me that it did not rain inside from condensation and that the plaster was still on the ceiling.

 

[Deere Dude]

On metal panels such as what yours look like, the edge shouldn't leak even without butyl tape. The edge of the panel with the foot has to be under and the other edge without the foot has to be over. Possibly the wrong edge is on top at the seam,

On the picture on the bottom, the left side of the panel with the foot should be overlapped by the side without the foot of the next sheet.

At least that is what I was told.

 

[s219]

On metal panels such as what yours look like, the edge shouldn't leak even without butyl tape. The edge of the panel with the foot has to be under and the other edge without the foot has to be over. Possibly the wrong edge is on top at the seam, View attachment 499957

On the picture on the bottom, the left side of the panel with the foot should be overlapped by the side without the foot of the next sheet.

At least that is what I was told.

I don't think it matters what type of panel -- I used PBR panel on my boat house and the manufacturer still called for butyl tape on all seams. Wind can push rain under that edge rib without some sort of sealant.

 

[yomax4]

Had the same issue. Pulled tin, Put down sheething, Ice dam rubbered the whole thing except for 18" from the ridge cap. No " condensation" in 9 years.

 

[mcgoo]

Had the same issue. Pulled tin, Put down sheething, Ice dam rubbered the whole thing except for 18" from the ridge cap. No " condensation" in 9 years.

Ya that's what my buddy said that's a roofer. The thing is at this point the metal needs to be repainted as well. So I might as well do it at the same time for the 2k is gonna cost.

 

[aczlan]

On metal panels such as what yours look like, the edge shouldn't leak even without butyl tape. The edge of the panel with the foot has to be under and the other edge without the foot has to be over. Possibly the wrong edge is on top at the seam, View attachment 499957

On the picture on the bottom, the left side of the panel with the foot should be overlapped by the side without the foot of the next sheet.

At least that is what I was told.

Not all panels are formed that way. I have actually never seen a panel with that "foot" and I have seen a lot of steel roofing.

Aaron Z

 

[SandburRanch]

Condensation can easily be determined, when there is visible water, by taking an air dew point temperature reading at that level and comparing that DP temperature to the metal surface temperature.

You won't necessarily need a silver cup or the mint for barn work. :laughing: A glass or AL container will work and when a piece of tissue sticks to the container dew has formed.

 

[Deere Dude]

Not all panels are formed that way. I have actually never seen a panel with that "foot" and I have seen a lot of steel roofing.

Aaron Z

There different types no doubt but that is the one I am most familiar with. Also the screw nearest the seam must be about an inch or so away for a better seam hold down.

I definitely thing butyl tape would be a good idea but the steel guy never advised it and I thought it was for corners and peaks and such.