"Invisible" leak in bathroom...

[Mustang]

Multifamily house; the plumbing for the 3rd floor tub/shower exists above the 2nd floor master BR. After tearing down the BR ceiling for unrelated reasons, I discovered that the 3rd floor bath has been leaking for a very long time (long enough to turn the piece of hardwood floor onto which the leak is falling black). The cast iron pipes still exist, but were replaced with ABS some time ago (I just purchased the 99-yr-old home in August).

It's a relatively modern tub (ex. not cast iron). The current tenant says the "tub" sometimes "makes a creaking noise." The bathroom has a splash guard between the wall and the tub, so water is not spilling over the side of the tub and seeping through the floor directly. I re-caulked where the faucet emerges from the wall, as that was loose...but the leak still exists.

It would appear as though water is somehow getting onto the top lip of the tub (in the wall), running to the front edge, and then running down the wood in the wall. Once the wood is saturated, the water starts falling onto the ceiling below.

My dad and I have had our heads jammed up into the floor looking for the leak for about 60 combined minutes so far with a variety of flashlights and groping around with our hands. I took a 15 minute shower while Pops looked/felt around, and he couldn't feel any water on the top lip of the tub (despite watching water fall at the same time)...so perhaps that theory is partially disproved. It doesn't appear as though any pipe is leaky, or that any part of the tub is cracked...

I've also recaulked the "splash guard," and the faucet's knob (as well as the faucet a 2nd time). I haven't yet recaulked the front edge of the tub, but again dad couldn't feel any water up there so I'm not sure whether that's worthwhile.

I'm at a loss. I'm trying to avoid calling in a plumber who also can't see any leak, and redoing the entire 3rd floor bath (or cutting a hole in the 3rd floor bedroom wall to access the back of the shower, as I have tenants there right now). Any ideas for other possible things to check, or solutions?

Attached is a rudimentary drawing...unfortunately I am without a decent camera right now.

 

[havasu]

This is going to be extremely hard to diagnose by way of a drawing. I would encourage you to beg, borrow or steal a camera and post up what you really have. Remember, water will run downhill through the path of least resistance. Also, isn't the splash guard upside down?

 

[Mr_David]

If the tub spout or valve is leaking in the wall it could be tricling down to the tub and tracking under the tile to the skirt and then down to the floor

Here's how you can test it for leaks .
Remove the the tub spout and the shower head and cap the shower arm and the nipple stubbed out for the tub spout. Then turn on the Valve.

 

[phishfood]

What Mr. David said.

And, if the tubspout is a slip fit type, there is a decent possibility that the oring on that is leaking and blowing back into the wall.

 

[Mustang]

Also, isn't the splash guard upside down?

I'm not sure why you suggested this?

If the tub spout or valve is leaking in the wall it could be tricling down to the tub and tracking under the tile to the skirt and then down to the floor

Here's how you can test it for leaks .
Remove the the tub spout and the shower head and cap the shower arm and the nipple stubbed out for the tub spout. Then turn on the Valve.

Thank you, I'll try that tomorrow.

And, if the tubspout is a slip fit type, there is a decent possibility that the oring on that is leaking and blowing back into the wall.

I'm not sure what type it is, but my old man will know. We'll check that too...thanks!

 

[LiQuId]

Is it possiblle that the water damage you are seeing could be related to condensate ? you had mentioned this was an old home. or perhaps the water is from the external envornment ( rain and such ) ?

pictures would help for sure..

 

[havasu]

With your drawing, I assumed the upside down triangle was your splash guard. If so, the wider portion of the guard needs to be on the bottom.

 

[Mustang]

I will get a camera tomorrow...

Is it possiblle that the water damage you are seeing could be related to condensate ? you had mentioned this was an old home. or perhaps the water is from the external envornment ( rain and such ) ?

I've thought about that as a possibility, as I only saw the puddle on some days in the AM (never at night). But last Friday, I physically got in the shower for 20 mins while someone looked under the bathroom. The leak appeared at that point - so I assuming condensate is not the cause. Nor is rain for the same reason (also, there has been no correlation between rain and appearances of the leak).

With your drawing, I assumed the upside down triangle was your splash guard. If so, the wider portion of the guard needs to be on the bottom.

Ah, sorry. That drawing is looking head-on at the front of the tub, as if you were inside the wall. The hypotenuse of that "triangle" is actually a triangulated support for the top lip of the tub (there is a matching one on the right side, which I did not draw into the picture). The splash guard is actually mounted on the top of the tub, perpendicular to the angle of this drawing (so, you wouldn't be able to see it here). In real life, the wider part of the guard is, in fact, at the bottom (it's actually L-shaped, not triangular ).

 

[LiQuId]

I am referring to the posabillity of condensate from the shower heat meets the colder air in the tub void. though unlikely. or the posability that the pipes in the wall are sweating when running also due to condensate. Are there puddles or is it just damp ?

thanks for being open, it helps to assist.

 

[Mustang]

There is definitely a puddle, not just dampness.

 

[havasu]

I'm wondering if it may be just a simple fix by using some silicone around the trim ring on the shower valve?

 

[Mustang]

I'm wondering if it may be just a simple fix by using some silicone around the trim ring on the shower valve?

Something along the lines of this link? I've already recaulked that piece, but if the valve itself is leaking that's a different issue...

 

[havasu]

Ok. How about this. Take the trim off and turn on the shower. Do you see water physically leaking from the valve with the shower on? If so, that is probably your problem. Pull the valve and purchase a new one. If the water is dripping down onto the valve from above, it will be your shower head fitting. If the valve is not leaking from anywhere at or above the valve, then it may just be at the base of your shower pan.