Shower leaking in wall

[rocks911]

Ugh!

My wife noticed a "musty" smell in our bathroom and after investigating I discovered that the shower was leaking. There is an access at the base of the tub/shower that I looked through as my wife ran the faucet. She ran the faucet into the tub for a couple of minutes and I did not see anything dripping. Then I had her divert the water flow through the shower and began to see drips.

The house was built in the late 70's and I was wondering if the pipe that comes through the wall where the shower head attaches is sweated on the other end (inside the wall) or is it threaded?

I tried to turn it hoping it was loose but it wouldn't budge so I'm not sure what to do next. If it's threaded I figure I can loosen it, remove it and maybe tape it with silicone tape and hopefully that's it. If however it's sweated on then there is no option but to bust into the wall to make the repair, obviously I don't want to do that. So, threaded or sweated, that's my question.

Thanks for any help.

[Mikey]

I can think of 4 places where it might leak when the flow is diverted. Is there an access panel behind the shower? If so, use a light and a mirror to inspect everything back there to see exactly where the leak is. If not, consider making an access panel...

To answer your question, the odds are almost 1.0 that the shower arm is threaded on the end in the wall, into a threaded elbow attached to the framing. If you take off the escutcheon around the arm, there may be enough room to see the joint, and determine whether that's where the leak is. If the escutcheon is large enough, you could enlarge the hole enough to see the joint, but small enough to cover up with the escutcheon when you're all finished.