Intermittent Shower Leak: Need some troubleshooting help

[herkdrvr]

Greetings Plumbing Forum Experts,

I need some help troubleshooting a plumbing issue.

About a week ago, we discovered a water spot on our dining room ceiling. We live in a townhome; directly above the dining room is the master bath.

We called a plumber who cut a hole. Despite running the shower, bath, sinks, and toilet...they could find no leak. We left the hole open for two weeks, no leak.

We were set to repair the drywall when four days ago, my wife happened to hear a metallic "ping". It was a drop of water while I was in the shower!

We called the plumber back out...he ran the shower for 15 mins. No leak. He left.

The last two days we have done some troubleshooting. The leak only occurs with the shower running. It can run for 15 mins dry as a bone and then when someone gets in the shower, it starts dripping.

Image: http://imgur.com/mu8FtN1

The pipe in the foreground has water run down the side, and then drip off the bend at the bottom. I think the white pipe is the shower drain (in the center of the shower) and off to the left (out of the picture) would be the shower faucets. They are not directly above the concerned pipe.

Video (not the best): https://drive.google.com/file/d/0B4T4uaBKPJL-NUZJRDFyLUN0Njg/view?pref=2&pli=1

[I will disable the video in a week or so]

What other troubleshooting steps should I take?

Thanks in advance!

 

[Jamesplumbing06]

The shower arm is threaded. I check this by removing the head only and getting a 1/2" female cap of any material it's temporary. Cap shower head and turn valve on. This pressurizes the shower riser pipe in wall.
On the shower arm pull the chrome ring back and look at those threads with a flashlight. That's the upper most part it could be. Next remove face plate on valve and look at fitting on top of valve going up towards shower head. Still can't find it? Shove a rag in drain and let pan fill up with shower water. The pan maybe cracked or the drain has loosened from fiberglass.

 

[Jamesplumbing06]

Sorry couldn't be drain. Almost has to be shower arm leaking inside wall. With head off turn arm counterclockwise. Clean threads. Get some Teflon. 2 maybe 3 wraps with Teflon. Then follow with a thread seal or even Vaseline. Your trying to make threads glide into each other so the Teflon digs into the threads.

 

[herkdrvr]

James,

Thanks for the reply. I'm not a handyman by any means, so I want to understand what you are saying.

Are you suggesting I take off the shower head, cap it off, turn on the shower and then clean the threads on the shower arm (i.e. where the shower head was)?

You think it might be leaking from the very top?

Edit to add: The shower is controlled by a single knob.

Much appreciated,

Herk

 

[Matt30]

Spray the tub surround and controls down with copious amounts of water. Simulate water splashing off someone's body while they shower, see if water appears.

 

[herkdrvr]

Matt,

Using the shower, I sprayed in a square motion, following the four edges of the shower where the shower base meets the tile. I sprayed for 5 mins & I positively ID'd leaking.

However, all the caulk etc. looks intact. I still have no idea where it might be coming from.

Do you have a "next step" to help narrow?

+++++++++++++++++++++
James: If I better understand your course of action, I might be able to try. I don't have a cap to shut anything off though.

Thanks!

Herk

 

[Matt30]

What type of tub surround do you have?

Caulking can look fine, but water only needs the smallest slit to make a mess. Is the caulk clear, or white? If I am caulking a tub, I always use clear, it's stronger. I only use white if I'm dressing something up, it doesn't have much strength.

Re-caulk the surround. Fill the tub with water before you start to add weight, then let it cure overnight,

 

[herkdrvr]

Matt,

To be clear, this isn't a tub, it's a shower. The caulk is white in some areas; clear in others. Obviously very old. I'm renting the home and honestly don't know the type of surround. Probably whatever the cheapest is. Tomorrow I'm going to get a bucket and try the water experiment again. It will help me eliminate the shower control. If it still leaks, I'll recaulk.

Thanks!

 

[havasu]

Keep in mind that when someone is standing in the shower stall, your weight will open up the smallest of seams.

 

[voletl]

You said you're renting the home? I would contact your landlord.

 

[Matt30]

You rent? Not your problem, or damage to repair. Call the landlord.

 

[Jamesplumbing06]

Yeah cap it just for test. Clean threads if your leak shows up in wall where shower arm is. But you said you found it by spraying. Remove all caulk from seam then recaulk every seam. Even around trim plates for valve.

 

[frodo]

.......................

 

[herkdrvr]

@Havasu: True, but using Matt's suggestion, I found a leak w/no one in the stall.

@Voletl: Contacting the landlord is how we got a plumber to come out in the first place via the home warranty. But they aren't troubleshooting much. *Sigh*.

@Frodo: Fantastic diagram. Where you are pointing to look for leaks is all behind drywall. How will I see that? The metal ring (where the shower arm meets the wall) is not fastened at all, but looking behind there is just a mash of insulation? The shower valve where you are pointing...I have no idea how I'd be able to look there.

I'll add some more photos.

Thanks!!

Herk

 

[frodo]

go around behind the shower. closet? bedroom? cut a hole

 

[herkdrvr]

Frodo,

It's a townhome. Behind the shower wall is another person's townhome.

Diagram: http://imgur.com/McUOSKi

I'll take pics a little later.

Thanks!

Herk

 

[frodo]

Frodo,

It's a townhome. Behind the shower wall is another person's townhome.

Diagram: http://imgur.com/McUOSKi

I'll take pics a little later.

Thanks!

Herk

then cut the wall in the shower

you said it ONLY leaks when the shower runs..

that would be the shower head riser leaking.

or the wall to tub seal , you said you eliminated the wall

all that is left is the 2 ares i pointed out


if you have a landlord contact him

 

[herkdrvr]

Frodo,

Landlord was contacted before I did any troubleshooting. They called the plumber (who did nothing) through the warranty company.

I believe you re: the shower head riser. I'm going to buy a cap today, run it, and see what happens.

I'll update once that is complete.

Thanks again!

Herk

 

[havasu]

Just understand that if something goes wrong, it will be your responsibility to repair any and all damage to your neighbor's property. I would not be playing around any plumbing problems when it is not your responsibility.

 

[herkdrvr]

Havasu,

Excellent point. Maybe I'll take a breather.

Herk