Hello everyone.

I've read this one before, but I have a similar problem yet it might be different.. here goes nothing.

We have a constant leak in our family room, which is directly below the bathroom and our children's bedroom. Upon further inspection, removing part of the ceiling where the leak has discolored the drywall, we see the elbow joint of a PVC vent which leads upstairs inside the wall behind the tub but between the rooms. I focus my flashlight up inside the exposed cavity showing the elbow joint more clearly, and can see that the water (which is very very lightly streaming down) begins from further up the pipe. I investigate further by heading upstairs. I enter the kids room, open the closet, and remove the drywall which is fit somewhat loose (so to get at the pipes behind the tub of course) and notice the PVC vent is showing signs of this same very very light stream of wetness. Now I decide to head to the attic, which the entry point is directly above me in the same said closet... poke my head inside with my flashlight to find where the water begins. There are no signs of wetness eminating from inside of the attic... not from the PVC vent, no sign of water on the insulation, not under the insulation between the vapor barrier and wood... no stains from past water... nothing!

I've recently had someone in to look at this problem. It was suggested that it may be condensation from cold air in the attic, warm air in the PVC vent, and that the condensation starts from within the wall where the heat and cold meet. The drip is slow and at night time is somewhat steady. It doesn't matter if it is winter, or summer, if it is raining, snowing, or hail... it comes back eventually again and again.

The solution suggested to me was to add an extra 20R rated insulation crossways to the already 20R insulation in my attic. It's an older house from the early '70s so.. It was also pointed out that the trusses were jammed with insulation, and that because this has been done, no air can rise inside and draw out through the vents above... which essentially is the culprit for the moisture retention, and build-up of condensation on the pipe within the wall - "cold meets hot". One more bit to add on top of putting more insulation in the attic was to wrap the PVC vent in the attic with insulation as well.

Could someone please let me know if this all sounds correct? I would really... really appreciate the assistance. We're re-doing our family room, and until we can this straightened out we're at a stand-still.

Just out of curiosity, are there any heating or air conditioning units located in the attic?

HVAC installers are notorious for drilling holes in plumbing vent piping to discharge condensate drains from heating units, air conditioners, humidifiers and heat exchangers.

Just a thought.

There are no heating or air conditioning units located in the attic.

Our furnace is located in the basement, and our air conditioning unit is located at the rear exterior of the house.

Keep thinking... that's all I can say. I'm hoping that you've read what I wrote, and that it made some sense. If it can help to relate more clearly, I can post some images.

Let me know.

;)

I was convinced it was condensate until I read, "It doesn't matter if it is winter, or summer, if it is raining, snowing, or hail... it comes back eventually again and again."
As a rule you don't have condensate on vent pipes in warm weather. You have tracked the source to the kids room and lost it in the attic. You're so close. I'm very interested in the source of the leak. Can you look farther? Let me know, Tom

I will go one better... tonight I will take a few photos showing the main areas of concern. Something more - we don't use and have not used the shower/bathtub in 2 years. When we moved into our home, it was evident that there had been a leak (where the current leak resides)... but was poorly patched over with stucco that didn't match the already stucco ceiling. We cut open this surface of drywall and exposed the hidden vent pipe, carrying the very tiny stream of water... which eventually when it gathers enough water causes a drip. This stream of water is such a slow process from a hidden starting point, that it's hard to consider it could be a leak from a pipe internally.

Anyway... I'll post some images this evening.

Thanks to everyone for their input so far. It's not over yet... but I am feeling better knowing that an answer is coming soon.

I locate a tiny and hard to pinpoint leak by taking a piece of toilet paper and starting at the top working my way down. The TP will pick up the slightest hint of moisture so when I see a wet spot on the TP I know I have located the source of the leak. Good luck, Tom

Does this only happen when there is precipitation? If so, perhaps it is coming in the vent and subsequently leaking through a hole in a hidden portion of the vent. You could put a U bend on top of the vent to see if it solves the problem.

Now this might sound like frustration but I've had this conversation before with several people. My point being is that I don't believe this to be a leak from the roof top, not water getting into the vent, and I'm left wondering about how much of my drywall I am going to have to rip off the studs to pinpoint the leak. I am also certain that it isn't a water pipe spraying towards the vent. They are in proximity of one another but do not share the exact location - being separated by drywall and studs.

I will post some images shortly to show what I am referring to.

Thanks again folks. If it were this easy to find the leak, then maybe I should have been a plummer... yet still considering on calling one if not resolved soon.