Most custom tile shower leaks aren’t a mystery to me anymore. After opening up walls and pulling tile on shower pan failures across Colorado Springs, I keep finding the same three installation mistakes. None of them were visible when the shower was built, but each one was bound to fail eventually.
Colorado Springs is harder on tile showers than a lot of places, but not for the reason people usually assume. This area sees more than 100 freeze-thaw cycles a year, days that climb above freezing and nights that drop below it. That’s real, and it’s brutal on the outside of a house (siding, concrete, decks, foundations). But it has nothing to do with a shower wall inside a heated home, since nothing behind that wall ever gets cold enough to freeze (that’s a mix-up I have to clear up on almost every shower call I run). One local factor for some showers is hard water, but only for homes on a private well. Colorado Springs city water is soft to moderately hard, about 1.3 to 2.8 grains per gallon, so this isn’t a citywide issue. Wells in outlying areas like Black Forest, Falcon, and Monument can run much harder, and that hard water leaves mineral deposits that break down grout and caulk faster. On top of that, every shower goes through its own heating and cooling cycle: hot water heats the tile and grout each time you shower, then they cool back down between uses. That repeated movement, at every tile joint, happens in every shower everywhere. For homes on well water, the hard water just speeds up the damage it causes.
Here are the three reasons custom tile showers leak in Colorado Springs, and how to check yours.
Failure 1: No Waterproofing Membrane
Tile is not waterproof. Grout is not waterproof. Neither is cement board, which is the substrate (the surface underneath) that most tile gets installed over. The only waterproof part of a properly built tile shower is the membrane: a continuous waterproof layer, either a sheet or a liquid coating, installed between the substrate and the back of the tile. It stops water from ever reaching the wood framing behind the wall.
In a shower built correctly, water that gets through the grout hits the membrane and drains down to the shower pan drain. It never reaches anything it can damage. In a shower with no membrane, that same water soaks into the cement board or drywall behind the tile, then reaches the wood framing. From there it causes rot, mold, and structural damage. Eventually you get a soft, spongy spot on the floor next to the shower, a stain on the ceiling below, or a shower wall that flexes when you push on it.
Most tile showers in Colorado Springs homes built before 2000 have no membrane at all behind the tile (I can count on one hand how many of these older showers I’ve opened up that did). Many homes built after 2000 still only have green board (a moisture-resistant drywall) or plain cement board for protection. Both of those resist moisture better than standard drywall, but neither one is a waterproof membrane. A tile shower installed straight over cement board, with no membrane, will eventually leak. How long it takes depends on the grout quality, how well the shower is maintained, and how much it gets used. But it’s not a question of if it leaks. It’s a question of when.
How to check: Do the tap test. Knock on the tile on the lower part of the shower walls, starting at the floor and working up about 18 inches. Tile over solid, dry backer board (the cement board behind the tile) makes a solid, dense sound. Tile over damaged backer board, whether it’s wet, delaminating (its layers separating and losing their grip), or rotted, sounds hollow or dull instead. If one section sounds hollow while the rest sounds solid, that section is worth a closer look.
Failure 2: Grout at Plane Changes
Every spot in a tile shower where two surfaces meet at an angle, like the floor-to-wall joint, the inside corners, or the joint where the curb meets the wall, is called a plane change. At each of these joints, the two surfaces move slightly against each other every time the shower heats up and cools back down.
Grout is rigid. It doesn’t move. Applied at a plane change, grout cracks under that movement because it’s being asked to bridge two surfaces that expand and contract separately. Every time you shower, the hot water heats the tile and grout at these joints, then they cool back down after you’re done. That repeated heating and cooling, in any climate, is what eventually cracks rigid grout at a plane change. For homes on well water, hard water speeds up the cracking by making the grout more brittle over time. Once the grout cracks, water gets in every time the shower runs, since that joint is wet every single use.
The right material at every plane change is 100% silicone caulk. It’s flexible and waterproof, and it can handle that movement without cracking. Most production-built showers use grout at these joints instead, because it’s faster to install and looks more uniform. That’s exactly why they fail faster, and it’s the single most common callback I get on a leaking shower.
How to check: Look at the joint where the shower floor meets the wall, including the inside corners. Look at the joint where the curb meets the wall. If you see grout at these spots instead of a flexible caulk line, those joints are at risk. If the grout there is already cracked or missing in places, water has already been getting in. The fix: remove all the grout at that joint, let the area dry out completely, then replace it with color-matched 100% silicone caulk.
In Colorado Springs, check these caulk joints once a year and plan to replace them every 3 to 5 years, even if they look fine. The constant movement is enough that silicone eventually wears out, even when it was installed correctly.
Failure 3: Inadequate Shower Floor Slope
The shower floor has to slope evenly toward the drain the whole way: no flat spots, no high spots, no dips where water can collect. Code requires a slope of at least 1/4 inch per foot, and no more than 1/2 inch per foot (steeper than that gets slippery). On a 36-inch square shower floor, with the drain in the middle, that means the outer edge should sit at least 3/8 inch higher than the drain, and no more than 3/4 inch higher.
A shower floor that doesn’t drain fully leaves standing water sitting against the grout and caulk joints between every use. In a well-maintained shower, with the grout sealed and the plane-change caulk in good shape, that’s manageable. But in most real showers, where the grout hasn’t been sealed in a while and the caulk has aged, that standing water becomes a constant moisture source. Over time it weakens the tile’s bond to the wall, breaks down the grout, and can eventually compromise the membrane underneath.
The slope problem is worse for homes on well water, since hard water leaves more mineral deposits behind. As standing water evaporates slowly from a low spot, it leaves mineral deposits (scale) behind. That scale builds up in the grout joints, gives mold and mildew a surface to grow on, and physically wears down the grout over time.
How to check: After the shower dries from use, look for any spot on the floor where water pools instead of draining away. Pour a small amount of water on the floor and watch where it goes. Any flat spot, or any spot that drains toward the wall instead of the drain, needs to be fixed. If the rest of the tile is in good shape, a licensed tile contractor can sometimes fix minor slope problems by adding a layer of mortar under new tile to build up the low spots, without tearing out the whole shower. If the slope problem is serious, the floor usually has to come out completely and be rebuilt with a properly sloped base before new tile goes down.
The Flood Test: The Definitive Check
If you want a clear answer on whether your shower pan is leaking, not just guessing from the symptoms, do the flood test. It’s the same test I run before I’ll ever quote a shower rebuild.
What you need: A test plug or rubber stopper sized to your drain (available at plumbing supply stores for $10–$20), tape, and 24 hours.
Process:
- Plug the drain tightly.
- Fill the shower floor with 2 inches of water.
- Mark the water line on the wall with tape and note the time.
- Leave it undisturbed for 24 hours. Don’t use the shower, and don’t run water in nearby plumbing.
- Return and compare the water level to the tape mark.
What it means: If the water level matches the tape mark after 24 hours, the pan is watertight. Any drop means water is leaking through the pan somewhere. A drop of more than 1/4 inch means an active leak. A very small drop could just be evaporation, since Colorado’s dry climate means some water evaporates even from a plugged, standing pool. To rule that out, repeat the test with plastic wrap sealed over the water. That stops evaporation, so any drop this time is a real leak.
What Repair Actually Involves
If the flood test fails, or the tap test finds hollow sections, how much repair you need depends on where the failure is.
Isolated caulk failure at plane changes, membrane intact: Remove the failed caulk, let the area dry completely, and apply new 100% silicone. This is a repair you can do yourself, as long as you’ve confirmed the membrane behind it is still intact.
Grout failure throughout, membrane intact: Regrout the shower floor, replace the grout at plane changes with silicone caulk, and apply a penetrating sealer (a sealer that soaks into the grout to help repel water). This is a bigger job, but it doesn’t require removing any tile.
Failed or missing membrane: There’s no surface-level fix for this. The tile has to come out, the backer board comes out, the wood framing gets checked for damage, new backer board and a new membrane go in, and then new tile goes in. Cost in Colorado Springs: $2,500 to $6,000 for a standard shower, more if the framing damage reaches the subfloor.
Slope correction: This depends on how bad the problem is. Minor slope issues can sometimes be fixed without tearing out the whole shower. Bigger slope problems require removing the floor and rebuilding it.
There’s a big cost difference between catching a failing shower early and finding it late. Early, when the leak is still limited to the pan area, a shower with a hidden leak typically costs about $3,000 to rebuild correctly. Wait two more years with the leak going undetected, and the same shower can cost $8,000 to $15,000 once you add in subfloor replacement, framing repair, and fixing the stained ceiling below. That’s several times the cost, for the same repair, just because it went undetected longer.
Do the flood test this week. It takes twenty minutes and tells you exactly where you stand, and I’d rather you find that out now with a bucket of water than have me find it later behind your tile.
For a free assessment of your Colorado Springs shower or a written estimate on bathroom tile work, call (719) 243-9718.
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