Leak around outside of vent pipe, leak is not from roof.

[Jstarzy]

Hi all...I’m new to the forum and would appreciate some member help with a puzzling problem....

I have a water leak coming down the outside of a 1-1/2 “ white PVC vent pipe. The pipe penetrates the roof, takes a right angle in the unheated attic, goes horizontal for about 2-3 feet, right angles down through a tight penetration into a wall in the closet below. The other side of the closet wall is a shower stall on the 2nd floor. The pipe continues down and penetrates below the 2nd floor flooring. I have the ceiling below opened up and this is where the dripping is happening, at the outside of a 90 degree elbow where the vertical pipe connects with a horizontal run, venting the drain from the shower (I think).

There is no evidence of any leak from the vent pipe boot at the roof whatsoever. As the leak was dripping from above at about a drip every 30 seconds, I went in the attic, the pipe was bone dry. As far as condensation, the penetration into the attic is tight, no gap, but isn’t sealed with foam.

There isn’t any real pattern to the leak. It’s random. It doesn’t seem to be associated with rain. It leaked more in cold weather when the forced hot air furnace was running but still, no smoking gun that I can find. As a matter of troubleshooting, I regrouted and re-silicone sealed the adjacent shower seems at the corner where the walls come together and where the raised shower rim meets the outside of the wall the pipe is located in.

Any thoughts? A leaking coupling I’m not aware of in the closet wall above? Condensation? Water leaks from the shower? The shower drain is not the culprit. Both it and the supplies are bone dry. I can see them in the open ceiling. The leak is coming down from above, no question.

Help! I’m stumped. The dripping is minimal but enough to ruin the ceiling Sheetrock.

Any help will be much appreciated!

Thanks. Jim.

 

[Kreemoweet]

Speculation is pointless, you're going to have to open walls and expose the pipe until you find the leak source.
I would bet on an inadequately glued fitting joint allowing condensation inside the pipe (which will be quite
abundant in cold weather) to leak out and run down the pipe.

 

[Sponsor]

 

[Jstarzy]

Thanks Kreem....of course I'm trying to avoid a messy sheetrock job in the closet but yes, it may come down to opening up that wall. The leak was down to two drips yesterday but yes, it's still happening and seems to be happening a little bit in rhythm with the HVAC running. This is leading me to believe it's condensation and perhaps a loose or disconnected boot or coupling in that closet wall as you suggest. The only other less messy fix would possibly be sealing the penetration in the cold attic, but it's pretty tight even without any spray foam.

Appreciate your suggestion...still open to others before I get the sheetrock knife out.

Jim.

 

[Reach4]

Thanks Kreem....of course I'm trying to avoid a messy sheetrock job in the closet but yes, it may come down to opening up that wall.

You would probably want to put in an access panel in the closet, rather than a sheetrock job. There are many to choose from.

 

[Jstarzy]

Hi...I’m just getting around to finishing up this thread. To be thorough, I checked the roof and sealed some cracked vent pipe boots and especially the one on the pipe that’s leaking. Even though this sealed the pipe at the roof, it, the outside of the pipe was still leaking in the house.

So...I opened the wall in the closet above and sure enough, a pvc coupling about 4’ Above the floor was never glued at the bottom joint. It took 2 6X6” openings in the wall to fix it. One to find it and the other to repair it with a Fernco boot. I Also learned quickly that the boot has to be secured with a nut driver. Fastening it with a screwdriver couldn’t get it tight enough to keep the pipe dry. Now it’s tight and dry and I’m finishing the Sheetrock job in the ceiling of our main floor at the original point of the leak.

Again...All of this due to an unglued bottom coupling joint and a condensation leak on a pvc vent pipe.

Thanks for the help all!

I hope this finished thread helps others that might have similar trouble...Jim.

 

[Jadnashua]

In some places, they want the vent pipe's diameter to be made larger for a section before it exits the roof. In areas where it can get really cold, the most air exhausting the vent pipe can create hoar frost, and literally plug the pipe up. That can cause other problems with the plumbing system.