The other evening I stepped into the walk-in closet and was surprised to find water dripping from the ceiling. Based on the location of the rooms and walls, I quickly realized the bathtub/shower is located directly overhead and my teenage daughter was taking one of her long showers. I ran upstairs and asked my daughter to turn off the shower. I had the kids use another the shower in a different bathroom until I could work on the problem the following weekend.
Dripping Water Stain on Closet Ceiling
Finding the Water Leak
My suspicion is the leak was coming from either the shower water supply or drain plumbing. The problem is that I had no access to the shower plumbing as it was sealed behind the drywall – often there will be an access panel, but there was none. I would have to cut a hole in the drywall in order to examine the plumbing.
Aside: I recently had the “pleasure” of fixing a leaking shower drain in the master bathroom
Showers and bathtubs can be creative in the way they leak. It’s a matter of remembering that water runs downhill and tracing the leak to the source.
Cutting an Inspection Opening in the Wet Wall
I began by locating the center of the wet wall (i.e. wall with the plumbing). I gently probed (don’t want to puncture a water pipe!) for wall studs by driving a small finishing nail through the drywall to see if it contacted a stud, moving the nail about one inch left and right until I had cleared a 6 inch length. There shouldn’t be framing studs in the center area of the wet wall to allow room for the shower valve – and I found my assumption was correct.
Locating the Wall Studs
Here’s a closeup of the nail and test holes.
Checking for Wall Studs
Now that I had confirmed there are no wall studs in the center section of the wet wall, I used a Rotozip spiral saw to cut a small inspection hole in the drywall.
I cut only a small hole because:
- I would have to repair the drywall later and small holes are easier to fix than large ones.
- Wallpaper is hard to repair as seams will show.
- I needed to locate the plumbing and wall studs before going further.
Cutting an Inspection Hole in the Drywall
The small inspection hole (above) allowed me to reach inside and locate the wall studs and plumbing; I also confirmed there was no electrical wiring in the wall. The inspection opening was enlarged to the span the width between the wall studs to dimensions of ~10.5 inches wide and ~8.5 inches tall.
Inspection Opening Cut in the Drywall
Below is a closeup of the hot & cold copper water supply pipes and the PVC overflow drain for the bathtub. An immediate concern are the greenish/white streaks on the copper pipes from dripping water. The pipes were dry and at this point I wasn’t sure if this were a historical artifact or recently made.
A strip of blue masking tape was applied to the bottom edge of the opening to reduce the amount of drywall dust rubbed off on my arms.
Bathtub and Shower Plumbing
Water stains on the drywall ceiling below the bathtub are apparent in the photo below. Click on the picture for a larger view.
Water Stains on the Drywall Ceiling below the Bathtub
Checking the Bathtub Drain for Leaks
A flashlight and mirror are used to inspect the bathtub drain for leaks. The bathtub was filled with several inches of water and allowed to stand for 15 minutes. No leaks were found at the bathtub drain.
Inspecting the Bathtub Drain for Leaks
Checking the Shower Plumbing for Leaks
I turned on the shower and used the mirror and flashlight to inspect the copper piping, shower valve and shower head arm. Bingo! Lot’s of dripping water coming down.
Inspecting the Shower Valve for Leaks
Below is a picture of the shower valve with wet streaks and water drops ready to fall. (Click on the image for a larger view.)
Uh Oh! I thought. If the shower valve is bad then I’ll have to cut another access opening in the drywall in order to replace the valve. That would be an ugly drywall repair. Notice the water stains on the drywall and chalky deposits on the copper pipes. The drywall integrity was fine – dry and solid – in spite of the water stains. I gave it a good shot of Lysol to discourage mold.
Upon careful inspection with the flashlight and mirror, I was able catch a glimpse of the water dripping from the shower arm (i.e. up high by the shower head) onto the shower valve. Good – at the least the shower valve is not leaking.
Water Dripping from the Shower Valve
Water is dripping on the subfloor from the shower arm and elbow in the photo below. The white stuff on the 2×4 base plate is drywall dust.
Water Dripping onto the Subfloor
Here’s a view of the shower head. The leak is coming from inside the wall at the connection between shower arm and elbow.
Shower Head
The shower head and wall flange were removed to get a look at the plumbing inside the wall.
Shower Arm
Source and Cause of the Leak
After reattaching the shower head, the shower was turned on and the source of the leak was plainly seen. The leak was coming from the threaded joint at the shower arm and the drop ear elbow. Click on the image for a larger view.
Leaking Water at the Shower Arm & Elbow
I unthreaded the shower arm from the elbow and observed that:
- The shower arm was threaded-in very tightly – this is good.
- The threads were sealed with pipe joint compound – also good.
- The pipe joint compound had become brittle and dry, this is what caused the leak.
The shower arm as it was removed is pictured below. The pipe joint compound is the white stuff in pipe threads.
Shower Arm before Cleaning
Fixing the Leak
A brass-bristle wire brush was used to clean the old pipe joint compound from the threads of the shower arm. Brass is a soft metal and won’t scratch the nickel finish. The shower arm was polished with a cotton cloth.
Shower Arm after Cleaning
The threads are sealed with teflon plumber’s tape. Wrap the tape clockwise (with the pipe end facing you) so the tape won’t unwrap as the shower arm is threaded into the elbow.
Wrapping the Threads with Teflon Plumbers Tape
The shower arm threads wrapped in Teflon plumber’s tape. I preferred Teflon tape for this job over pipe joint compound because I wouldn’t be able to get a wrench on the elbow to really tighten the joint – and I felt that Teflon tape does a better job of sealing gaps in the pipe threads.
Shower Arm Threads Wrapped in Teflon Tape
The old pipe joint compound was cleaned from the drop ear elbow before reattaching the shower arm.
Drop Ear Elbow for the Shower Arm
The shower arm was threaded into the drop ear elbow inside the wall and the shower head reattached. The shower turned on the connection checked for leaks. No leaks! Problem solved!
Checking the Shower Arm for Leaks
Installing a Maintenance Panel
The ugly inspection opening in the drywall was covered by 12 inch by 12 inch white return grill purchased from Lowes. The grill can be easily removed for maintenance or repair if needed in the future.
White Return Air Grill
Here’s a better perspective of the bathtub/shower and wet wall with the newly installed white grill.
Wet Wall and Bathroom
The final task is to paint the downstairs closet ceiling to cover the water stain.
I hope this knowledge saves you some money,
Bob Jackson
March 22nd, 2009 at 7:40 pm
Hey very nice blog!! Man .. Beautiful .. Amazing .. I will bookmark your blog and take the feeds also…
October 25th, 2009 at 9:57 pm
Hello,
Thank you for such a riveting article!
I just bought a house, that has a leak behind the shower wall, and I wanted to see if anyone else had fixed a similar problem. Happily I found your terrific article. And I realize it’s a lot bigger task than I could ever hope to accomplish on my own. I especially like how you made the detection hole large enough to locate the source of the leak but small enough to cover with a pretty Grill, in case you needed to go into the wall again. That was clever! And great to follow along with your photos…
Thanks again for the great insight.
Penny in Las Vegas.