Do you have a shower that has a pan, or is it a one piece unit? If it has a pan, it could be leaking at the base of the pan seeping out to the inside of that area of drywall every time the shower is used. If it is a slow seep and seems to dry between periodic showers, but gets wet more quickly due to continous shower use, then that could be your problem. Please give more details on your shower type, but it would be wise to pull out the affected drywall and check for possible mold issues as well.

It's a cast-iron tub, with a Swanstone tub surround.

I thought it was some sort of seeping from the pipes or at the tub surround, because it did seem to get a little bit dry-ER (but never dry) between showers, and wetter after several showers in a row.

We have an opening into that wall, and no apparent mold issues. Yet.

I forgot to ask if you are on a slab foundation. If so on homes out here,old and new, they box out where the tub drain is and it is left exposed to the soils beneath. There have been cases on homes that have tubs in an area of an exterior wall where moisture ,or even water from saturation/heavy rains where it got extremely wet under the tub areas enough to travel up and wet the drywall. Just a thought if you have had more than your fair share of rains and are on a slab w/ a similar setup. They still use this deranged method out here on new homes, but being in the desert, seepage/flooding is pretty rare though it does happen. Caulking seems to be the only reason it doesn't seep out to the flooring, but the moisture travels through the slab and damages floorings as well. Pulled many tubs on remodels that were pretty gross underneath!

no slab--it's a 1921 apartment building (we own our apt)

That slab plan sounds pretty stupid!

We never had this problem before; then we had the tub surround and the shower fixture changed, and shortly after that it began. Not TOO "shortly after"--but close enough that it made me wonder if there'd been a joint in the pipes that failed.

But no evidence of that INSIDE the wall (at least, so far--I've asked DH to open up a bit more of the wall).

I took some pics; I'll post them.

Without actually looking at it, I'm not sure how much help you all can be in actually finding an actual leak.

But the biggest question I'm still hoping people can answer is, can drywall stay wet for weeks?

can drywall stay wet long?
simple answer:
NO
Now its just a matter of WHEN it gets ugly, spongy or moldy enough that you HAVE to repair it.
good luck and enjoy!
Reid

Drywall cant take moisture,let alone being wet for any length of time. It's risky at best loading up sheets and on the way back to the project, it rains and the top sheets get wet enough to where you generally lose them,( man, i knew i should have brought the tarp!). Anyhow, when it gets wet and dries, it gets brittle to the point that it is weakened and basically will crumble. You need to pull out the affected drywall and try and solve the moisture/wet issue and replace all drywall that has gotten wet. It will forever be unreliable and im surprised it has hung in there this long. The price of drywall has gone back down and has never really been a high dollar item. Painting over the damaged drywall is only a band aid fix. Do it right and replace the rock that got wet. You might consider repalcing w/ green board (m.r. wallboard) as it can hang a little better than standard board, but when staurated, even it will fail after a while. Your concern isn't whether the drywall can hang if wet, it's to get to the source of the leak no matter what it takes as there are other considerations such as your floor/subfloor and wall framing that could eventually be affected. There is always the chance of mold in hidden areas that you might not be seeing. Bite the bullet, start pulling sections to get to the source. This might be way more involved than you think, picking at it isn't going to solve the puzzle.

Your concern isn't whether the drywall can hang if wet

That wasn't even my original question.
I know it's not strong now; and it isn't good for it to get wet.

Maybe I should have asked "is it physically possible for moisture to stay in drywall, without evaporating out, for weeks?"

or

"doesn't it dry out in a week or so?"

or

"If it gets really wet once, how long will that moisture stay in the drywall?"

Because we can't find the leak, and I'm wondering if it's at all possible that the water that was in the drywall was from a one-time puddle on the floor that got wicked up into the drywall?

"is it physically possible for moisture to stay in drywall, without evaporating out, for weeks?" NO, unless the source of the moisture is keeping it wet.

"doesn't it dry out in a week or so?" It could dry out in a day or so but it will be brittle.

If it gets really wet once, how long will that moisture stay in the drywall?" Dependent on the humidity in the area and the temps, but normally dries out in a day or two.

You stated in your original post that it is drying out, then getting wet again dependent on the shower schedules. A one time puddle on the floor would dry, so would the drywall.

This is as frustrating as when your car doesn't start. You dont know if it's the battery, alternator, cellinoid and is a matter of tracking down the problem. Best of luck, been there!

If drywall is allowed to contact a tub it will eventually draw water up into it and get mushy. Drywall should not be used in any part of a shower area below a height of 3 or 4 ft. If it is used it should be held up from the tub edge 1/4" so when the silicone sealant inevitably fails the drywall will not get wet.

Thanks, sierraeast--that tells me that this problem can't be the result of an occasional puddle on the floor. And I can lean harder on the idea of investigating further.

We just haven't been able to recreate it at all--except that this morning, that spot was the teensiest bit damp--for the first time in 3 days. I *think* DH doesn't leave a puddle on the floor from his shower, but your answer will make it possible for me to argue that we have to keep looking.

The wall on the tub side is cement board; the drywall is around the corner from it.

I think I'm going to use everyone's comments, all together, to convince DH to just rip out all the drywall and replace w/ cement board.

Great idea w/ the cement board. I know a lot of drywall contractors are using it now days where green board was used in the past. Greenboard is okay, but as mentioned, will fail if it gets saturated enough. Cement board seems like a more reliable material. Best of luck!

You mentioned that this is a cast iron tub with a swanstone surround. Does this cast iron tub have an integral tiling flange to it? If not, there's your problem right there. Tubs without tiling flanges aren't meant for tub/shower usage and will have leaking problems if installed in a shower situation.

I discovered last night that it does have an integral tiling flange. (this tub has served in a shower installation without problems for years; it was only after we changed the surround--a few months after)

the cement board sits inside the flange, and the Swanstone is attached to the cement board.

That's on the wall that is IN the tub.

The drywall in question is outside the tub. See, that wall is a freestanding wall that sticks out into the middle of the room at the end of the tub; it was only built to enclose the shower pipes. The end of the wall and the back of the wall are drywall. (and the top, natch)

I think we've pretty much concluded that there are no leaks in the pipes. There doesn't seem to be ANY water that's gotten behind either the cement board or the tiling flange.

We think what's happening is that water is running down to the tub--on the outside of the Swanstone, where it collected during the shower--and then trickling over (running along that tiling flange) and dripping down the side of the tub right at the corner where the tiling flange ends.

The caulking at the bottom of the Swanstone was not well done; my attempts to fix it may have made things worse. I don't know if breaches in the caulk at the very bottom would strengthen a "wicking" process to move the water out tot he edge or not.

And I'm not positive that there was much of a breach there anyway (I spent last night cutting away silicone and installing one of those plastic strips).

It seems like a LOT of damage for a single shower's worth of splashing at a time, but there's a water trail there that looks clearer and clearer the deeper we dig.

DH is balking at ripping the drywall off, but the more I investigate it, the more soggy stuff I find, and even the 2x4 framing in that area is trashed. Only about 2 inches worth, not the whole wood by a long shot--just the part at the bottom, of course.

DH was really hoping not to have to disturb the cement board and the Swanstone. He's afraid that removing the framing will mean we have to disturb that wall, and he doesn't want to.

I sort of would *like* to do that wall over, bcs I think we might get a much better seal under the bottom edge of the Swanstone, and that might minimize the opporunity for water to travel there.

I think I'm going to try to tuck some toilet paper or something into the water trail, and see if it gets damp.

Does the tub/shower have a curtain or a door? If it's a curtain, it's very possible the water is making its way along the inside edge of the tub and over the far end. I'd drape a towel over the edge of the tub (if you have a curtain) to see if water is escaping during a shower.

I would doubt the water is getting behind the Swanstone since it's sitting on the inside edge of the tile flange.
My guess is something is going on with the valve that is within the wall. I'd first remove all the trim on the shower control and then turn the water on and see what happens. Also check the tub spout and make sure it's not leaking around the threads. If there are no leaks and you continue to get water on the floor and drywall, I'd remove the drywall on the opposite side and inspect the pipes.

Why do you say the 2x4's in that area are trashed? Just because they got wet doesn't mean they need to come out. Take off the drywall, let them dry and then redo the sheetrock wall.

One more option: if you want to test the caulking area, put a strip of duct tape or heavy packaging tape around the inside edges of the tub. After a few days, you'll know if that's the problem area!

I have inspected the pipes--that was my very first assumption. I can look inside the wall--remember, it's free-standing. And there was already a hole in the wall by all the valves & stuff, from when it was all installed. If something is happening w/ the valve, it's happening on the shower side of the cement board, and dripping between the cement board and the Swanstone, bcs nothing on the back of the cement board is wet.

I reapplied one of those self-adhesive plastic strips that substitute for caulking to the water wall.
I think I got a really good seal; it sure *looks* tight all along it.

Just before my shower today, I tucked a strip of toilet paper into the pathway down the outside of the tub at that corner, the pathway that I think is where the water travels. It was soaked after my shower (and I was really careful w/ the shower curtain at that corner). So water it still traveling down that groove.

So now I just have to figure out how the water is traveling. I think I'm going to just apply a caulk "dam" at certain points to be sure water can't go there, and see if it changes anything.

The 2x4 has gotten so wet that it can be crumbled into pieces with just a fingertip and medium pressure, that's what I mean by trashed.

I think we'll try taking off the trim on the shower control. DH resisted when is suggested it, but

(I don't get water on the floor--well, once or twice, but I was never sure if that was drips and splashes from the preteen, or seepage from the wall.

I'd meant to add--part of why we thought it wasn't the valve, but is the splashing against the Swanstone wall, is that when we ran the shower with no *person* in it, we couldn't get water to move.

But more checks are in order.

We also have water leaking out of the shower area when showering. My solution was to get in the shower, run a wet hand just off the edge of the shower down the tiles and then "glue" the shower curtain to the wet edge, no more water running down the edge of the tub.

That's what I do before I even get into the shower.

So I know the problem is not random spray bouncing out into the room.

It's got to be something that is running along to the top of the tub near that tile flange.

Though it's hard to "glue" it at the bottom corner of the shower wall where it meets the tub--and that's where it's leaking.

So any little amount of random spray *could* get out there (not much, and not easily), and of course there's nothing stopping anything on the tub itself.

How about if one takes a shower and the other one watches, if nobody gets carried away maybe you can see where it's leaking.

I'd remove the caulk between the tub and the swanstone and then re-caulk it when the tub is full of water (yes, you might have to get in the full tub). Leave the tub full until the caulk is dry. The weight of water (and a person) can make caulking fail.

If it were me, I would try running a hose from another source and start spraying it on the walls at the farthest point of where the water leak is appearing. Then gradually move it closer to where the leak is showing up,and mark that point. Even then it could be difficult to find the exact point of the leak. But you will conclude that it is absolutely not the pipes in the wall that are leaking. The leak could be just like a leak on a roof. Just because you see a spot on the ceiling doesn't necessarily mean that is where it is coming from. Water can travel along ways before it hits a weak point of entry or exit.

Hendricus, I'm not sure we'd be successful--probably somebody would get carried away.

Also, whatever this is, it's a seep, not a stream. it's happening INSIDE somewhere.

Brody, that's not a bad idea--but I just applied one of those "caulking" strips, and it still *looks* pretty well sealed. I'll remember it, though, when we get to the final "put it all back together" stage.

No roof leaks, decker173; this is a second-floor apartment, and the water arrives after a shower, not after a rainstorm.

I'm trying to get a hose that attaches to the tub spigot--but of course, if the valve is leaking, the hose won't help much. I don't know what other source of water to use, though--not sure how to get a hose to attach to the bathroom sink, and I can't get one long enough to reach around the apartment building, up to the second floor, and in to the bathroom. Well, maybe I could--but I'd need 2 floors worth of hose.

I tried testing the assumption that this is splash water from the wall, that runs down to the tub, and then out and over the edge (bcs there's a tiny slant to the tub). So I caulked a dam at the edge of the tub. Water has built up there, but it's not THAT much, and the pathway down is still wet.

I'm justing having a hard time believing that THAT much dampness can arrive on the wall below the tub from THAT source.

I *finally* got DH to agree to take the escutcheon plate off the valve part of the fixture, to see if the valve is leaking. It turns out that, since there was no water or wetness or anything behind the cement board, he thought that meant it couldn't be the valve. So I'll try that.

Once I said, "of course not; the cement board is impervious, no water CAN get behind it. But it can run down the FRONT of it, between the cement board and the Swanstone."

Usually the faucet spigot has a collar with a screen in the that can unscrew. Hardware stores should have an adapter to screw into that and the hose. If not, I guarantee water bed stores carry those adapters. I had one. But then again, do they still make water beds? Shows you how old I am.

maybe using food dye in a pitcher of water so you can see it better, the 2x4's been getting wet for a while to crumble. you have found one source, running down the side of the tub. maybe tape some paper towels to actually see how wet it's getting. and for how long can the drywall stay wet?, water on the backside, no air movement, a long time, the in the room side could feel dry to the touch but the back never completly dries out.

Just curious, did you ever solve the leak issue?

We're still trying. We had company this week, and just couldn't deal w/ pulling the cabinet out of the way, unscrewing stuff, etc.

That "company is mom and dad, so I showed Dad my problem this morning. I suggested he and DH (who is based at home) can take off the

I do get some puddling on the top edge of the tub at that corner--not a lot, about 1 tablespoon worth--after 2 showers. But it doesn't seem like quite enough to make it as wet as it sometimes gets. Maybe it could, but it just seems like not nough, and not concistently enough....

Also, today the wet area was more than damp, but the water from the tub could not have dripped down, bcs I ran a tall bead of caulk there to stop it (and it did stop some water--but not enough to overflow).

If they don't take escutcheon plate off today and look at the valve, maybe I'll try to look at it tonight.

well, DH & my dad took off the escutcheon plate, and apparently the foam ring was damp, and wasn't a complete circle--and inch or two was missing.

And Dad says there should have been a rubber gasket by the faucet--I'm not sure if he means the handle, or the spout--can't be the spout, it's below the problem area, so he must mean the handle of the faucet.

So it would seem that, between the lack of seal between the metal faucet plates & the Swanstone or backerboard (but it will have to be the Swanstone, bcs the cement board is crumbled at the hole), and the slope of the tub on the inside of the shower, that this dampness is coming from a lack of seals.

It just seems weird to me that it can get that wet from just the splashes of water off our body in our 7- to 10-minute showers. (or DD's 25-minute ones)

In every escutcheon I've installed, the foam on the back is never complete. Because of that, I always apply a thin line of caulk around the the plate......just in case. Handles should have a seal/gasket.

Like you, I can't imagine that much water draining down the shower-head wall!

I still think something's going on inside the wall..........

I thought we *had* caulked around the escutcheon. Good to know about the foam.

BUT....the foam was wet, so that means water got in. And if there wasn't a seal or gasket on the handle, then of course it would continue to travel.

We can look right inside the wall from the opposite side--there's nothing going on on the actual pipes. Nor is the framing near those pipes even damp.

Framing could remain dry if you have a strong drip that's falling directly to the floor.
The piping to the showerhead, including the extension connection, isn't leaking either? If it's not the pipes, then check the level of the tub and the seams of the surround (vertical & horizontal).

In the meantime, I'd keep a dry towel on the floor where you think the water is running off the edge of the tub. Continue this and see if the drywall stays dry.

If the surround seams aren't leaking, the water is possibly runoff due to the tub not being level. But if you didn't have this problem with the tub when it had the old shower wall, it's strange that it's starting now.
Once you rule out any other source, I'd be very suspicious of the surround and would have the installers return. (Or was this a DIY?)

DS once had the problem of runoff from the tub edge and ended up using a splash guard. Doesn't look that great, but it worked.
Other option would be a shower door.

Here is a link that might be useful: splashguard

I put a jury-rigged splash guard there--just a dam I built out of caulk; and some water does pool behind it, and can't just run over the edge. The tub isn't perfectly level; it's possible it settled some when the tub surround was replaced; we also reglazed the tub, etc., so maybe it shifted the teeniest bit.

But the plaster is still wet, even after I put in that dam.

In fact, after yesterday's look at the pipes, the tub spigot wasn't sealed to the tub itself anymore; unfastening the handle part let it shift. I taped a strip of plastic wrap above the handle (sticking out pretty far on each side) and fastened it in place w/ duct tape; then I put a second one to cover the tub spigot (which has the pull-up button to make a shower)--though the tub spigot is LOWER than the spot where the wetness starts.

The wall under the plastic wrap was dry, but the plaster was STILL wet after showers.

So that cannot have been water dripping through the holes where the faucet is.

I'm starting to wonder if the handle valve itself is leaking. I'm trying to figure out how I can tell--maybe pack the cabinet w/ cotton balls, and see if they get wet?