Gradual leak between second and first floors - any ideas?

July 27, 2010 3:09 PM

Verrrrryyyy slooooowwwwly accruing water damage on our first floor ceiling. What gives?

Over the past year or so, a water stain has been very, very slowly growing on the ceiling of our first floor, somewhat under a bathroom but not directly under a bathroom. We've had a few plumbers come to take a look, and they all said they thought water was seeping through the tile in our bathroom, so we took several measures to stop getting the floor wet (and sealed the tile as well). The plumbers all mentioned that the very slow rate of the water damage indicated that it wasn't a leaking pipe. We also tested the shower basin and it is intact. The leak is still happening, although we actually bought a moisture reader and it never 'reads' as moist anymore - or we never 'catch' it reading moist anyway. We marked the outer edges of the water stain a few months ago, though, and the water stain has expanded in all directions.

I'd say after about a year it is now 1 foot by 6 inches in size. It's not very dark, but getting darker. After we thought we fixed it, I 'cleaned/removed' the stain with a bleach/water mixture so it first I thought that was just reemerging, but now it is clearly a large stain than before. What the heck gives? Any ideas? Who would you call to figure it out?

posted by n'muakolo to home & garden (16 answers total)

Is it worse when the A/C is running? It could be condensation from an air duct.
posted by Some1 at 3:15 PM on July 27, 2010

Similar problem here with my basement ceiling.

We found out our roof was leaking and not only damaging the first floor ceiling but going down the walls to the basement ceiling as well. Water will follow a path until it's absorbed somewhere. It just happened to appear in the basement ceiling first!
posted by thorny at 3:16 PM on July 27, 2010

If not a leaking pipe, I wonder if condensate on the water line could be the problem. If not condensate, could rainwater be getting in and scooting along a water line somehow? How old is the roof? If you have attic access, it might be worthwhile to take a peek and see if there are signs of leaking.

If it were me, I'd cut out the stained sheetrock of the ceiling. You might get a better idea as to the source of the leak if you can see what's going on up there. It's easy enough to do and (reasonably) easy to repair afterwards.

(on preview, what Some1 and thorny have said)
posted by jquinby at 3:19 PM on July 27, 2010

It might not just be water seeping through the tile floor - it could also be the tile in the tub itself. Make sure to check the tile an cauk on the side of the shower where the knobs and shower head are. Water bounces off the body when you shower.

(as we learned to the tune of a 500 dollar tub retiling. )
posted by robocop is bleeding at 3:30 PM on July 27, 2010

You could also have leaky bathtub or shower faucet valves that leak into the wall only when they are open. Had that one on a kitchen sink and it did a lot of damage to the cabinetry before I realized what was going on.

No matter what the source it's likely that there has been much more water (and likely water damage) inside the wall along the path from whatever the source is.
posted by localroger at 3:34 PM on July 27, 2010

We had this problem when something was wrong with our shower head. The water came out through a light fixture in our hallway, which was not directly under the bathroom (I'm still not clear why). So, seconding localroger.
posted by dpx.mfx at 3:41 PM on July 27, 2010

Also, you only can exclude that it's a leaking pipe/leaking connection, if you actually look. Some pipe- whatdeyacallthem, cuffs? joints? drip at a very slow rate, some only drip when warm, some when cold etc. I find it a little cute that your plumbers ruled out this possibility. It's just as possible that the slow rate indicates that most of the stuff - but not everything - has seeped away elsewhere. (To illustrate the last point: I've had a major medium-term leak in an expansion thingy under the roof that left almost no stains down below for days, until something started actually dripping just below the leak itself. No idea where all that water went. It's 8 years later, still no idea).
posted by Namlit at 3:42 PM on July 27, 2010

Yeah, pipes can definitely leak slowly.
posted by rhizome at 3:49 PM on July 27, 2010

Had the exact same experience as robocop is bleeding. Took forever to figure it out. Good luck.
posted by baho at 3:58 PM on July 27, 2010

Check for cracked/worn shingles or bent flashing anywhere in the vicinity of the leak -anywhere above and within 20 feet of the stain. Water can follow some pretty byzantine pathways to it's final destination.
posted by bonobothegreat at 4:02 PM on July 27, 2010

Do you have central A/C? If so, your primary drain line is supposed to drain into an existing drain (usually via a bathroom), but can get clogged - algae is a big problem here - in a way that it won't re-route to your secondary (outside) drain. This has, in my experience, caused very slow drips into the ceiling.

It's MORE likely to be shower (or sink or toilet, don't forget those) leakage, but that's an avenue you may need to explore.
posted by Lyn Never at 4:16 PM on July 27, 2010

Thanks for all these ideas. Getting us thinking.

I think it IS worse when the A/C is running, so that theory is moving to the top of my theory list.

I suppose it's possible that the shower floor tiles are leaking (through the walls of the shower?), but I would think that would mean that the shower basin is leaky, and the shower basin passed the water test. It is a good three feet by five feet away from the bathroom so I would think that if it was the bathroom the stain would most likely appear below the shower/bathroom floor but I know very little about plumbing....

This sounds like the solution involves cutting into a lot of dry wall, or god forbid, taking apart some tile. Hopefully just cutting into the stained area will at least help us figure out the source of the leak!
posted by n'muakolo at 4:20 PM on July 27, 2010

Cutting into the ceiling is WAY easier than disassembling your bathroom tile. Plus it needs to be replaced anyway, right?
posted by Aquaman at 5:18 PM on July 27, 2010

Cutting into the ceiling and peering in with a flashlight was my first thought, too. However annoying it is to replace drywall overhead (or to pay someone to do it), I'd want to follow it to its source to make sure that no water-related nastiness was building up.
posted by slidell at 7:23 PM on July 27, 2010

I'd cut into the ceiling, but to do that, you might have to accept either having a giant bill and a large part of your ceiling ripped out or having a hole in the ceiling for a while.

We had something similar happen. We bought our house three years ago, and when we moved in, there was a small water stain on the ceiling. It didn't seem like a big deal--it was dry, and just a stain, so we figured that something had leaked at one point and the ceiling was never fixed.

Flash forward about a year and a half. One night I walked into the dining room and looked up to realize that the ceiling had a bubble in it, just by the water stain. I grabbed a chair and poked it, and out poured about a gallon of water.

We have a very slow, intermittent leak coming from something in our shower. Sometimes it happens, sometimes it doesn't. We'll go a month without any dripping at all, and then it'll drip with every shower for a week. Or it'll drip for my shower, but not my daughter's or partner's.

We've had three different people in here, and the consensus is that without an ongoing leak, they're happy to take apart the ceiling to find the leak, but we're looking at a huge bill and the need to totally rebuild our ceiling. The last guy suggested that we just wait until it becomes a more regular problem so that someone can come out and see where the leak is/what to fix, and in the interest of minimizing the expense and inconvenience, that's what we're doing. It does, however, mean that we've had a bucket sitting under the leak for the last eighteen months, just in case.

I'm not trying to discourage you from opening up the ceiling, but I did want to point out that just peering in with a flashlight may not be sufficient, especially if you--like me--have an older house and aren't ready or able to commit to a much larger undertaking.

All that said, check the area next to the tub, especially if you have kids. Though it wasn't ultimately the source of our problems, we did learn that it was somewhat common for the wall/floor next to the tub to get wet, then drip the water onto the ceiling of the room below.
posted by MeghanC at 8:18 PM on July 27, 2010

As for why it might not be below the source: water can run along horizontal elements (eg joists) in between floors. So the water could drip down onto a joist under your sink, then run horizontally along the joist for 8 feet until it hits a suitable spot in the wood, then drip down into the ceiling of the room below.

Depending on the age of your home, you might have polybutylene pipe which degrades and can leak. (I learned this after my own mysterious ceiling stain became the ceiling-bubble-of-water and the nice plumber came and cut a tidy hole in the ceiling, replaced the pipe, and said we should let the ceiling air out for a few weeks to be sure it was completely dry)
posted by LobsterMitten at 10:36 PM on July 28, 2010