a few days ago I noticed water pooling in the ceiling of my bathroom. I pulled away the drywall to find a PVC pipe venting to my roof had unseated itself from a 90 degree elbow.

After re-cementing the pipe to the elbow, there is still a very slow leak coming from the other end of the elbow. I've confirmed this isn't a roof leak as water is not dripping down onto the PVC itself.

Some additional details: it's a very tight space to access the pipe, I suppose I could pull down more drywall as an option, but I'd like to keep that to a minimum. So I feel as if I have two options:

  1. Use an epoxy putty around the leaking side of the 90 degree PVC elbow; or
  2. Replace the elbow with a long sweep elbow after cutting out the faulty elbow

If 2, given the fact that the pipe is connected to a fitting in my roof, I'm a little hesitant to use a hand saw. Luckily this pipe isn't used for pressurized water or the like.

Thanks in advance!

Image of the leaking elbow, notice the drop on the right side of the elbow.

  • 1
    Is the pipe loose in the elbow? Maybe there is enough play to pull it apart half an inch, re-cement it and slide it back together. What's weird is that vent pipes shouldn't have water. Maybe you could just put a rain guard on the pipe on the roof. Nov 19, 2021 at 5:49
  • I did my best with the small size of the hole to pull them apart but wasn't able to get them apart. I was told I could use heat to help but that the PVC isn't "usable" after that Nov 19, 2021 at 15:59

2 Answers 2


The bigger the gob the better the job - just slather the outside joint with pvc cement.

I've had abs pipes that I've glued and had small leaks and just slathered the outside and had it seal up. The abs and pvc glues actually melt the two plastics together.

Worst case it doesn't work and you need to go with something more drastic.

  • I wound up using the epoxy putty but I suppose some rain or shine blue PVC cement would have worked as well. It hasn't leaked since I applied it last night so fingers crossed! Nov 19, 2021 at 18:35

Maybe some super glue can enter the gap. If it has to flow against gravity, a strong hairdryer or leaf blower could force the glue up into the gap. A mirror helps for visible control.

Super glue has a low viscosity, hence would easy enter by capillary forces.

A face shield is important when working with super glue, especially if working over head.

Before application, the connection should be dried, f.e. with a hair dryer.

BUT: If that white insulation fiber material is asbestos, measures against spreading those fibers are necessary.

Watering with a flower sprayer (some dish washing substance or soap added) does help a lot.

Asbestos has been often used in old houses which were built or renovated before the ban.

  • @Nelson "Asbestos isn't an airborne toxin." Are you sure? Everywhere the danger of asbestos is described as being the microscopic particles that enter the lung resulting in cancer.
    – xeeka
    Nov 22, 2021 at 21:33
  • I'm re-checking the facts and medically it actually functions like a toxin, but it is due to the body's inability to process and get rid of it that it causes problems, and it takes 10 to 50 years to show symptoms. Breathing it in will have them permanently lodge into your lungs and eventually your lungs will scar and can even turn into cancer. By and large it is due to it being broken up, gets airborne, and breathed in. If you suspect asbestos, DO NOT MESS WITH IT. Get it inspected. DO NOT RIP IT OUT, DO NOT TOUCH IT.
    – Nelson
    Nov 23, 2021 at 1:52
  • When I say "get it inspected", it means you contact the government to come and deal with it, NOT rip off a piece and go to a lab.
    – Nelson
    Nov 23, 2021 at 9:51

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