Strange New Ceiling Leak Around Air Conditioning/Heat Vent (floor, roof, pools)

[nicwright79]

Just yesterday I noticed our ceiling in the kitchen directly under our guest bath was leaking around the vent. There doesn't appear to be anything wet or leaking in the upstairs bathroom. Even after showers, using the toilet and running the faucet, the water doesn't appear to drip more or less. The air conditioning was not running at all yesterday when the leak started. We did have quite a bit of rain yesterday. I just don't want to spend an arm and a leg on a plumber if this is something we can fix ourselves. Any help would be great.

[texdav]

Often if you have a slow leak it can buildup and come out at a compaletely different location. I would get it checked because a constant leak could mean mold. If it wasn't there before the rain ;I would suspect a leak in the roof but yopu nevber know. I get up in the attic and look for a leak.I have seen roof leaks that came out at light fixtures even.Should be a water spot and wet wood where the leak is in the roof ;if that is it.

[Bergenite]

Could be a leak at the roof at a plumbing vent stack flashing.

[harry chickpea]

My bet would be a corroded or damaged trap under the shower, or a leaking mixer valve. Pretty common.

[nicwright79]

How do we check that out?

[nicwright79]

And would it be hard to fix ourselves?

[rubytue]

Originally Posted by Bergenite

Could be a leak at the roof at a plumbing vent stack flashing.

This gets my vote. Heavy rain, leak around the vent stack, water runs down the side of the stack and then drips when it hits a p-trap, the water then pools on the top of the drywall, then runs when the pool gets big enough. You see it around the a/c vent b/c thats where it had an exit.

As for checking it out/fixing it - go up to the attic and find the vent stack, then look to see if its wet or there is water damage. If so, then you'll need to get up on the roof and fix the flashing. Also, grab a ladder, remove the vent cover and hopefully there will be a gap between the duct and the vent cover, shine a flashlight in and look around for signs of water damage/mold. If you see water but no mold, do whatever you can to try and dry that area out (you may have to be inventive). If there is mold, you'll need to replace the drywall in the area of the mold.

If you don't find anything in the attic to indicate a roof leak, then go with Harry's theory and it may take a plumber and be a big mess

[texdav]

Especailly look if the stack is one oif those rubber collars instead of a lead stack.They often leak as the rubber gets old next to the vent pipe.

[rubytue]

OP - did you find it?

[jimboburnsy]

Originally Posted by nicwright79

Just yesterday I noticed our ceiling in the kitchen directly under our guest bath was leaking around the vent. There doesn't appear to be anything wet or leaking in the upstairs bathroom. Even after showers, using the toilet and running the faucet, the water doesn't appear to drip more or less. The air conditioning was not running at all yesterday when the leak started. We did have quite a bit of rain yesterday. I just don't want to spend an arm and a leg on a plumber if this is something we can fix ourselves. Any help would be great.

I had a "leak" around the A/C register in the master bedroom about a year ago. This was pickling my noodle because there isn't a second floor or any pipes in that area. I had compromised insulation around my ducts that was allowing hot, moist air to directly contact the cold metal duct. Condensation was forming and running down the duct to the register where it found its way into the bedroom.

Sounds something like plausible, but you have a lot more possible culprits around a bathroom and the "no A/C" thing makes me more conservative...