5

I had a new roof put on last spring. I noticed some wet drywall last night in a bathroom and removed some. I found some wet insulation and wet framing near a bathroom vent. I narrowed the location of the water intrusion to the hole in the decking for the bathroom fan vent. See pics. I had already sealed the exterior of the vent in spring as the roofer hadn't done so. But water is clearly still infiltrating. I am not certain where the water is intruding from. Any ideas?

Vent Interior

Vent Removed

Exterior 1

Exterior 2

Improve this question
2
  • 3
    Poorly located and optimistically "sealed" penetration of the roof, so leaking is not too surprising. Throwing 3 more tubes of caulking at it is unlikely to fix the leak, IMHO.
    – Ecnerwal
    Commented Dec 30, 2024 at 19:38
  • It's hard to make up for poor planning after the fact.
    – SteveSh
    Commented Dec 31, 2024 at 11:53

2 Answers 2

Reset to default
6

It is really unfortunate that the vent cutout caused the need to cut into the standing rib of the metal roofing. The vent cutout should have been located in the center area flat space between the standing ribs.

The best way to fix this would be to relocate the opening to between the ribs and then removing and replacing the whole sheet of the roofing that is impacted. If the metal roofing was installed as a replacement roof after the original construction then there should have been better planning to relocate the roof penetrations appropriately.

The other two plumbing vent pipes coming through the roof look like they were not optimally placed relative to the standing ribs in their area.

It is possible that it may be a way to achieve some type of bandage type fix for this that would last some years. I'm sure there are multiple ways that this could be attempted. If it was my roof I could consider some type of metal flashing installed with hot roofing tar between the flashing and a clean roof metal as a kind of a tar sandwich. One thing that aggravates this type of repair is that ideally any flashing is installed under the metal roofing on the up slope side and on top of the metal roofing on the down slope side. In the process I would relocate the roof penetration appropriate and then try to repair the standing ribs with flashing formed and installed in the proper way.

Improve this answer
8
  • Interesting. I didn't even think about the effects of cutting a rib. I wonder if the roofer will stand by the work and fix this. Thank you.
    – ian
    Commented Dec 30, 2024 at 20:59
  • As a follow up, when researching this topic, I came across a video showing a standing seam roof with a cut rib with a vent protruding. The roofer is very clearly not concerned about the cut rib and uses an elaborate "boot" to seal the vent. Is this a code issue or best practice issue? I want to have some confidence when confronting the roofer. Skip to 7:30 in the video. youtube.com/watch?v=BPanZpBXIrY
    – ian
    Commented Dec 30, 2024 at 22:21
  • @ian - The products and techniques used in that video are excellent. The dog house box placed over the standing seam works very well in that example due to being able to tuck the top edge of it under the up slope metal. In your case the best solution is still to move the roof penetration over into the flat field of the sheet metal so you can use a sealing boot similar to the first part of that video. Unfortunately the cut rib you have would necessitate replacing the roofing metal sheet. It may be possible to cut the whole width of the sheet above and below the damaged (continued)
    – Michael Karas ♦
    Commented Dec 31, 2024 at 0:17
  • (continued from above) area and install a partial length sheet that is pushed up under the remaining up slope sheet and over the top of the down slope sheet. A potential reasonable solution in the case that there is a spare cutoff piece of material left over from the original install.
    – Michael Karas ♦
    Commented Dec 31, 2024 at 0:19
  • Thank you. I have several different locations where a rib was cut for a vent. I only have 4 metal panels remaining and therefore not enough panels to replace and do this correctly. Hopefully the roofer will come to an agreement with me!
    – ian
    Commented Dec 31, 2024 at 0:25
3

The thing about roof seams is that they aren't totally watertight, some small amount of the rain can get inside and flow along the internal profile to the gutter. If the seam is interrupted then this water needs a place to escape.

For this, the flashing should form a flat area below where the seam is cut to allow the water to escape.

Improve this answer
2
  • Yeah, I think the roofer goofed here by not installing some kind of sealant on at least the seams with penetrations.
    – Huesmann
    Commented Dec 31, 2024 at 14:48
  • that can work too.
    – Jasen
    Commented yesterday

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.