Water leak in the wall behind a shower
A shower's tap pipe connections sit behind the shower's wall, posing a threat of leaking at any time. A soggy shower wall, water stains on the wall behind the shower's tap or on the wall or ceiling directly below the tap and musty smells in the shower all can point toward a possible leak in the wall.
A leak in the shower's plumbing behind the shower wall may go unnoticed for months. Once you realise that a water leak exists behind the wall, you need to take action immediately. Water leaks can cause the platerboard behind the shower's surround to deteriorate, requiring you to remove the surround and install a new wall. The leaking water may also cause mould to grow in the shower wall, which will weaken the wall studs and put off potentially harmful spores into the air.
Confirming the source
To confirm that you shower's tap is leaking behind the wall, you must access the bottom of the shower, either from an unfinished basement below or through the subfloor, allowing you to see the shower's drainpipes. One person watches while the other turns on the tap but directs all of the water from the tap into a large container or removes the shower drain's cover and stuffs a wet rag into the drain opening. With no water running down the drainpipe, any leaks the person watching from below sees must be from the shower's tap connections.
Cutting an access panel though the wall that sits directly behind the shower's tap will allow you to access the tap connections without damaging the shower's surround. You must not cut into any studs in the wall when you create the access panel, which you can do if you probe into the wall with a finishing nail first. Drill into the wall to give your jigsaw's blade an opening to go into, and then cut out a panel area. You must install a swinging door over the opening, allowing you to access the shower's plumbing later.
From the access panel you created, you can observe the leaking tap connection up close. If the leak comes from a loose pipe connection, use a pipe spanner to tighten the connection so it is secure once more and no more water leaks out. Leaks in the soldered connections between pipes, or from pipes that have a hole, require the expertise of a plumber. Since you have already created the access panel, the plumber's job will be that much easier, costing you less money.