June, 2003
Inspection News and Views from the American Society of Home Inspectors

Inspecting Tiled Showers and Shower Pans


If home inspectors aren’t suspicious by nature, I believe they’ll come to be so after a few years in the business. And this serves us well, especially when confronted with a tiled shower. The perfect example is the shower stall pictured above. At first glance it appears to be typical for its type and age. The strainer is missing; there’s some minor grout deterioration; and the door has been given up for a curtain — all defects, but not necessarily major issues.  

But wait, there’s a minor stain at the ceiling below. Did someone leave the curtain out? Or run the toilet over? Or given what I know about tiled showers, does the stain suggest I should be considering more troublesome possibilities?

From experience, I’ve come to believe the difference between a good inspection of a tiled shower and a disastrous one is what we look for, what we ask ourselves, and what inspection techniques we use to answer our own questions.
After all, a tiled shower can be as expensive to repair as almost any other component in a house. More than most metal, fiberglass or other prefabricated stalls, the repair of a leaking tiled stall can easily run $1,000. With specialty ceramics or marble, the cost is even greater.

What’s more, removing tile, replacing the shower’s liner (the shower pan) and installing new tile can be just the beginning when these stalls leak. In fact the shower compartment pictured here cost the owner thousands of dollars for structural repairs, duct replacement and mold remediation work.  

Since much of the water ended up in a heating duct at the first floor, the only initial evidence of a leak was the minor stain at the ceiling below it. Testing revealed the lead shower pan sandwiched between the sub-floor and the tile work was defective. Later it was apparent it had been leaking for some time.

When I saw the stain on the ceiling, I asked myself about the possible source of the unwanted water. To find the answer, I eliminated all the plumbing fixtures in the bathroom other than the shower as the source. Next I employed a procedure used by many professional plumbers to eliminate from suspicion shower components, such as the drainpipe, shower arm or faucet stems. The procedure is described in the last section of this article, “Beyond the scope–locating a shower leak.”

In the first two sections of the article, “Inspecting the tiled shower” and “Shower pan basics,” you’ll find the techniques and information this suspicious home inspector relies on to meet the unique inspecting challenges presented by tiled shower stalls.


Signs of unwanted water from a shower stall differ according to its location in the home. Location can also play a role in the likelihood that a leak will be discovered before there is extensive damage.

Over a crawlspace

C-STALAC.gifWhite crusty stalactites dripping from soggy black wood – that’s a sight that sends a clear message to home inspectors. Often that’s how we know a shower pan is leaking into the crawlspace. Because these leaks are seldom discovered before the damage is substantial, the signs practically cry out to us as we scoot along inspecting the crawlspace. But even when there isn’t this type of blatant evidence, the flooring below a tile shower deserves our careful attention, especially the area around the drain. Leaks often show up first in the drain area. (Photo: Stalactites dripping from soggy black wood below a tiled shower — a common sight during a crawlspace inspection.)

On a slab

Shower pans above concrete slab floors also leak, staining baseboards or wood trim in nearby areas. In addition to stains, loose floor tiles in the bathroom or in areas sharing a common wall serve as a red flag. If a closet backs up to a shower, check its lower walls and floor for signs of water. Closets are often packed with stored items, allowing problem indicators at these areas to go unnoticed until the damage is extensive. Don’t be shy about asking to have things moved away from the common walls during the inspection. And when carpet covers the closet floor, check to see if it’s wet. If the carpeting is loose, rusted out tack strips could be the cause – another tip off to a leaking shower.

Above living space

When a shower is on an upper floor, signs of water on the ceiling below can’t always be distinguished from that of a defective wax seal or a misused shower curtain. Because upper level shower leaks are usually spotted quickly by the occupants of the home, the structural damage is generally minimal. There are exceptions, of course. Although reduced damage sounds like a good thing, it can be problematic for home inspectors, because the lack of visible damage makes it easy to overlook a leak. Some primer and a little paint can make the ceiling below a leaking stall look as good as new.

Be suspicious of new paint under a second floor shower. Also be suspicious of new and of very old pans.

Age of the pan

All tiled shower stalls deserve close attention, but those with new pans or pans 30 years old and beyond seem to generate the most repair work for plumbers in my area.

Improperly installed new pans or liners damaged during construction can leak soon after being put to use. Older pans do wear out. An old shower with a replaced pan is usually easy to identify from debris in the crawlspace and new plumbing below the floor. Without the benefit of a crawlspace, the pattern, style or sudden color changes in the tiles at the lower portion of a stall are indicators of a replaced pan.

Shower not being used

Let your suspicious nature work for you when checking out tiled showers. Something as simple as no soap or shampoo in a stall or a missing shower curtain can be a clue something is wrong. Dried stains can indicate an absence of recent water, and all signs of lack of use should be taken seriously. When you suspect the shower is not being used, a quick check with the owner might trigger a sudden recollection of a past problem, making further inspection of the stall unnecessary.

Reading between the lines

While inspecting the shower compartment, look closely at the inside corners for large vertical cracks or separations where the walls meet. Loose grout is often washed from these areas, and depending on the quality of the workmanship and material behind the tile, the spray from the showerhead can be channeled into the wall cavity. Washed out grout on the horizontal joints of the wall is also a reason to be concerned, and any missing grout or caulking can cause a substantial amount of damage if not repaired quickly. These cracks or open joints are usually easy to repair, if caught early with some grout or caulking.

Cracks, cuts, and thresholds

Tight horizontal cracks or thin breaks in the tile across an entire wall are common on older shower compartments. Typical settlement, expansion and contraction of the structure, is generally the cause. In my experience, these are only a minor leak concern, but I recommend trying to determine if the tile sections above and below these cracks are loose. Use caution as you run your hand over these cracks. They are often razor sharp. If the edges are determined to be a “cut hazard,” note this along with your level of concern for the actual crack.

On almost every shower pan I’ve replaced, I’ve observed damage at the threshold. Also known as the dam, a combination of traffic, loose door trim and deteriorated tile work can make the threshold highly susceptible to damage. Inspect it well. Once water penetrates this part of the shower, it breaks down quickly.


D-FLAKING.gifPressing and thumping the tile and picking at the grout to identify potential shower problems are important, but alone they’re inadequate techniques for finding problems. Experienced inspectors know to cover the shower strainer and add water to check the integrity of the shower pan. I would encourage inspectors to fill the shower to approximately 1 to 1 1/2 inches below the door threshold. Do this early into the home inspection, so the water has ample time to make its escape. (Photo: Note what you see at the ceiling and relate it to possible concerns to the shower above it.)

With upstairs’ showers, periodically spot-check the ceiling below once the shower base is filled. This prevents any major damage should the pan leak. But equally important, at some point a more careful visual inspection of the ceiling surface should be performed. Check it from different angles and with good light. This might expose hard to see stains and patches, which is sometimes evidence of a developing problem or a previous one.

Always note stains or flaking at the ceiling, and relate it to possible concerns about the shower above. Because of the expense of replacing a shower pan, I recommend to my clients further evaluation and testing if there is any doubt to the cause of the visual clues.

More than the pan

As for the faucet, check it for drips or leaks and note any loose escutcheons. If the shower arm is loose, point out how this increases the potential for a fitting leak. To avoid cutting the wall, plumbers often use a shower arm escutcheon with a setscrew as a temporary fix. By pulling the pipe up against the backside of the wall and tightening the setscrew on the front side, you can keep the pipe from bouncing around during normal use. It won’t eliminate the possibility that the fitting could be rung off when the shower arm and showerhead is being removed, so encourage your client to hire a professional for the job.

If a door is part of the fixture, check the hinges and hardware for soundness and proper function. This is important because broken hardware often creates unsafe edges. Doors and surround walls should be made of a safety glass or an equivalent, and doors should swing out into the room.

All the components of the shower plus nearby fixtures are considered if there are signs of unwanted water. Of all the components, the shower pan is usually the most difficult and expensive to repair. A review of shower pan basics explains why.


Unlike fiberglass, metal or other prefabricated showerstalls, most tiled shower compartments rely on an unseen liner installed between the tile and sub-floor to keep them from leaking to the structure. In years past, shower pans were known as “safes,” and they were made from 4-pound sheet lead, 24-gauge copper or even multi-layered 15-pound felt paper. From my experience, lead appears to have been the material most often used. Lead pans were heavy, folded outside the shower compartment, then lifted and set between the framed walls. In some cases, joints and seams required soldering.

E-LINER.gifToday the sheet material is plastic, and pans are folded in place. A quality shower pan not only covers the floor area of the compartment, but also has sides that turn up 2 inches or more above the finished threshold level. The inside corners are folded, never cut; and the threshold is wrapped in the liner material with a folded over lap of about an inch on the front side. (Photo: A common fold used at the inside corners of a shower pan.)

F-RECESSED-HUB.gifIn best cases, the floor area is sloped toward the drain opening. In some areas a concrete/mortar base is applied over the sub-floor, just below the pan, so the floor can be sloped toward the drain. But in many cases, perhaps to save time and money, the pan is installed directly over the sub-floor and only the drain area is tapered. (Photo: The liner is pulled over the recessed drain hub.)

G-CLAMP-RING.gifAnother critical area in shower pan construction is the connection of the drain to the liner material. The fitting used for shower pans sandwiches the liner material between the top of the hub fitting and a bolted flange called a clamp ring. This portion of the drain has weep holes designed to direct penetrating moisture into the drain below the strainer plate. The drain fitting works best if recessed slightly below the rough floor. (Photo: The clamp ring is pulled down with bolts at the topside. Weep holes around the ring allow moisture to be directed into the drain below the strainer plate.)

On older showers, the drainpipe extended through the hub and was sealed with a lead caulked joint. Some later drains used a rubber compression ring to seal the joint. But for many years, newer fitting designs allow the drainpipe to be glued or banded directly to the fitting itself.

It’s important to note that the floors of all tiled showers are not lined. Though the walls of the stall may be tiled, some showers use a prefabricated base called a receptor, which is made of molded stone, terrazzo, plastic or another material. Liners are not a part of this design.

Occasionally, with slab construction, a monolithic pour of the building’s floor and a shower receptor is formed. When this is done, the receptor is usually recessed, and the user may step down into the shower. A cut-away view of this type of shower would reveal that the concrete receptor is poured directly over the soil and it is unlikely that a shower pan will be employed for this type of construction.


Though not particularly complicated, the testing procedure described here is well beyond the ASHI Standards of Practice. But I believe home inspectors who already perform other types of intrusive investigations could certainly handle this procedure, which can be used to help locate leaks on tiled lined stalls and all other types of showers. As a plumber, I’ve used the method for years.

Pinpointing the leak

A good plumber rarely begins a shower inspection by sealing the drain. When a shower is suspected of leaking, a more methodic process is used to try to pinpoint the source of the leak. Because of the high costs involved in replacing a shower pan, it’s important to be sure that it is indeed the pan that is actually leaking prior to removing any tile. If another part is at fault, the costs of repairs will likely be less.

Stems, risers and gooseneck checked

Before turning on the faucet, the showerhead is replaced with a boiler drain or some other type of hose valve fitting. Using Teflon® tape to seal the threaded connection will allow little more than hand tightening to make up the joint, but pliers will likely be needed. With the boiler drain turned off and the faucet turned on, you can monitor the back of the faucet from the access panel. This will allow you to determine if the problem is with the shower riser or if the shower arm threads leak. With shower stalls above ceilings and especially those that lack an access panel, adding a pressure gauge to the set-up can cut the inspection time. Once the pressure to the attachment equalizes, shut off the shower faucet and watch for a drop in pressure.

The showerhead is replaced with a boiler drain or other hose valve fitting. Adding a pressure gauge to the set-up can save time and is helpful if there is no access to the shower faucet.

H-TOOLS.gifSolder joints on showerhead riser pipes are sometimes overlooked during the plumbing rough in. Yet because they’re under reduced working pressure and the joint is sometimes physically tight, they go leak-free within the wall for years before starting to drip. Shower arm threads can easily become loosened in the wall with an aggressive adjustment of the showerhead or the installation of a new shower massage unit. When this happens, the threads can leak each time the shower is turned on. (Photo: Tools needed for inspecting shower components.)

Faucet stems are a common source of shower leaks. If the faucet stems drip or the faucet cartridge or ball leaks and no clear view of the wall-concealed parts is possible, they should be corrected before any additional testing is performed. The trim or escutcheons of a faucet can funnel as much of this water behind the wall as outside it.

Testing the integrity of the drainpipe and trap

Once it’s confirmed that the stems, riser and the gooseneck are all leak free, a hose is attached to the boiler drain still installed at the gooseneck. With the strainer plate removed, a steady stream of water is directed down the drain, while avoiding wetting any other surface area. This part of the test helps determine the integrity of the drain piping and trap. Rusted out traps on old systems and improperly glued joints on newer ones are often found. The amount of time to flood the piping should be determined by the accessibility or view of the drain work. With concealed piping, give it 15-20 minutes before moving to the next step.

I-HUB.gifIf the drainpipe and trap appear sound, an internal pipe plug sets up the test for the older style drain fittings to the drainpipe. With the pipe plug in place, pour a little water around the lead, rubber or other compression type seal. Watch closely to see if it disappears. A loose or deteriorated joint seal between the pipe and fitting hub is a common area of water leakage. If the water disappears, the seal or joint is compromised, and it must be repaired before testing continues. If it appears solid, step into the shower and apply shifting weight around the strainer as an additional test. (Photo: An internal test plug installed in the pipe and a little water poured around the drain can sometimes determine if the compression seal, illustrated by the white ring, is leaking.)

Checking caulk

When it’s determined all these plumbing components check out, pull the plug. Then using the hose connected to the shower arm, test the walls and doors. Spraying water against glass partitions or the door can point out enclosure wall or caulking deficiencies. The large vertical cracks that are often found at inside corners should be well soaked. It’s sometimes best to step into the shower when directing the spray against the walls and doors and have someone watch the outside. If water leaks into the room from the walls, glass panels or door, make a note of the leak. It is not uncommon to find minor leaks that only seem to appear during this type of tough testing.

Unless a wall or door leak makes it impractical to continue, move to the final step of testing. Repairs at these areas tend to take a long time with caulking removal, replacement and set-up time. It might be best to let a piece of metal silver tape serve as a temporary repair, so the testing can continue.

Final step

The final step in the test procedure is to reinstall the test-plug and fill the shower base to about an inch or so below the threshold. While it’s filling, pay close attention to the surfaces around or below the shower. Sometimes the leak will appear slowly and may even require that the shower sit full for a couple of hours. But often the water will flow freely from the pan, and by quickly pulling the plug you can minimize additional damage to the surfaces below.

During each step of the procedures described here, the surface areas below and around the shower should be monitored and/or moisture tested constantly. A shower leak to a crawlspace will likely be identified more quickly than one to a ceiling or above a slab. With upper level showers, and those over slab floors, a substantial amount of water and more time for some steps in the procedure might be needed. Showers over slab floors may require pulling back some carpet in an adjoining room or closet.

Finally, leaks to any of the shower’s components discovered during the testing procedure should be considered as a potential source of the unwanted water, and not until the entire process is completed should the shower compartment be given a pass. If no leaks are discovered, other fixtures nearby should be checked out. Ceiling leaks can originate from a number of other sources but the purpose of the testing procedure is to help eliminate the expensive repair of a shower pan leak.