… is no way to be if you’re a shower floor!

So, here’s the deal. I usually try (sometimes unsuccessfully, but at least with a try) to be charitable (or at least polite) towards previous contractors whose work I’m often called on to repair or completely redo. Sometimes mistakes happen for explainable reasons, after all.

But sometimes you come across some work that can only be described as complete, unadulterated, and consummate dumbassery. This was one of those times.

The eventual fix is described in the next post, “Shower Repair Rescue, Part DEUX“. The rest of this post describes the problem in (hopefully humorous) detail.

Want a few ‘how the frack did that happen?’ chuckles with lots of advice for how to avoid shower install debacles? Then read on!

Tile Isn’t Waterproof (and neither is concrete)

First, a recap of some shower construction materials basics.

TILE AND GROUT ARE NOT WATERPROOF! While it’s pretty common practice to make shower and tub surround walls with surface tile bonded directly to concrete backerboard, it’s still a fact that neither grout nor concrete backerboard are waterproof. Concrete backerboard is at least moisture resistant, and unlike drywall it doesn’t contain paper and glue that offers food for mold. However, every time tile on concrete backerboard sees water there is some moisture that is transferred into the backerboard substrate.

This usually isn’t enough to cause a long-term problem in a concrete backerboard wall. The moisture that’s absorbed into the backerboard during a normal 5-15min shower usually completely dries back out (hopefully back out the tile and grout if there’s at least a proper moisture barrier between the backerboard and wall framing) before the shower is used again.

You do ideally want an actual waterproof barrier between the surface tile/grout and the backerboard substrate to maximize the life of a tile shower. But wall tile set on a concrete backerboard substrate even without a waterproofing layer generally isn’t a major problem.

SHOWER FLOOR TILE & GROUT ABSORB LOTS OF MOISTURE! The average American showers for ~10min start to finish at an average water flow rate of two gallons per minute (2gpm). So, that’s ~20gal of water dumped on the shower floor — the equivalent of four of these big 5gal home improvement store all-purpose buckets. Filled to the brim. And then completely emptied. Over and over again.

Think about this analogy. Your home probably has a 50gal water heater tank (the typical size for American houses). If nearly half the water in that tank was regularly dumped on your bathroom floor(s) two or more times a day, wouldn’t that be some scary shit? Even worse, what if that super-leaky huge tank of hot water was on the second floor of your home?

This is why showers absolutely must be properly waterproofed at the base and around the curb. There are several different methods for properly waterproofing tile showers, but more importantly there are LOTS of different ways to screw up the waterproofing.

THIS IS WHY SHOWERS FAIL! Water is lazy, and therefore always looks to go down as quickly as possible. If your shower floor has at least some kind of effective waterproofing and is at least mostly sloped towards a drain, then most of that 20gal will fall straight down the drain before it can cause a moldy, mildew-y, dry-rotty problem. And if water intrusion does start to be a problem, it’ll generally show up fairly slowly and with advance signs like excessive surface mildew or a pronounced between-showers musty stink.

However, if your shower floor has poor waterproofing, then a good bit of moisture will bypass the drain and instead simply go straight down through the shower base. This is what eventually causes major floor and/or wall framing dryrot problems.

Again, water is lazy. That’s is water’s weakness. But it’s superpower is persistence. Water never gets tired of looking for ways to get out of a container. Therefore, if it’s at all possible for moisture to get into the subfloor or wall framing of a shower or tub enclosure, then eventually it definitely will.

THANKFULLY, EVEN BADLY WATERPROOFED SHOWERS USUALLY FAIL RELATIVELY SLOWLY. Even a poorly done shower base will usually not cause major moisture intrusion problems right away so long as the shower floor surface tile is at least effectively sloped towards the drain with no dead spots. And, even a completely totally screwed-up base will generally announce itself with lots of nasty musty smelliness before passing enough moisture into the subfloor and wall framing to cause irreparable structural damage.

Those two “usually” and “generally” caveats are key, though. Sometimes, you’ll come across a shower install that’s seemingly diabolically designed to cause problems right away.

This was one of those times…

The Problems? All of ’em!

This particular install was like a master class in literally EVERYthing NOT TO DO when constructing a shower. I’d seen just about every possible mistake in previous shower fix jobs, but never nearly every mistake possible in one single job. If not for the extra $2-3K it cost the client to fix, the situation would have been comical.

Here were all the structural problems, ranked from least to most problematic:

ONE: Wall tiles installed unevenly with spotty thinset coverage underneath. The uneven grout lines would be obvious to anyone. The reason why was clear from tapping a few tiles and hearing lots of hollow echoes underneath. Whoever installed ’em was obviously struggling to get the large-format 12×12 tiles even kinda flush. The process of pushing and pulling and re-setting tiles in an effort to make them somewhat even will create lots of void spaces in the thinset between the tiles and the substrate underneath.

This was an annoyance but not a structural problem. So long as the tiles at least stay stuck to the walls, void spaces behind wall tiles is mostly a cosmetic issue. In fact, it’s something that can actually help mitigate the next issue:

TWO: Wall tiles set on concrete backerboard with no waterproofing or vapor barrier. This was clear from popping off the showerhead and handle trim for a look into the wall. Not having a moisture barrier in the shower walls isn’t great, but it’s also pretty common and not the worst thing in the world. It limits the life of a tile shower to ~20yrs max, but most bathrooms in a city like Austin, TX,  will be remodeled within that timeframe. So, definitely an annoyance but not an immediately scary issue.

THREE: No tilt to the shower curb tile. The homeowner was planning to finish the shower with frameless glass instead of a shower curtain. So, the tile on top of the shower curb definitely needed to be tilted inward a bit (like 5deg or so) to prevent water from pooling next to the glass divider. This is a fairly common mistake, but one that nevertheless indicates a sloppy careless install.

FOUR: Uneven shower floor tile work finished with unsanded grout. While unsanded is fine to use for shower wall tile with thin ~1/16in grout gaps, shower floors should never be installed with plain un-reinforced unsanded grout for many different reasons. A definite indication that the installer didn’t know what they were doing.

FIVE: No slope on the shower floor. Like seriously no slope at all. Dead flat. Completely level. This was clear from just, like, looking at the shower floor. It was why the homeowner originally asked the original contractor the question “Dude, why is the shower floor completely flat?”

This is a MAJOR problem! Job one of a shower floor is to help water find its way to the drain. Remember that water is persistent but also lazy — it generally mostly always obeys gravity, but even gravity needs at least 1/8″ of pitch per linear foot to show water where to go! So, major problem.

SIX: No waterproofing for the shower floor. Like, no waterproofing AT ALL. Apparently, the original contractor though that 1/4″ concrete backerboard would be completely impermeable to moisture. Which is, ah, completely totally wrong. Like, totally absolutely even super-easily wikipedia verify-ably wrong.

This is a SUPER MAJOR OMFG problem! Installing shower floor tile directly onto a layer of unwaterproofed backerboard laid directly on a plywood subfloor in a second-floor shower with NO SLOPE TO THE DRAIN AT ALL is literally beyond dumb.

Again, I usually try to be charitable (or at least polite) towards previous contractors whose work I’m often called on to repair or completely redo. Sometimes mistakes happen for explainable reasons, after all.

This was not one of those times. The person who did this work should be legally banned from every touching a shower again.

The Result? Pretty obvious!

The homeowner was apparently kinda suspicious of the whole flat shower floor thing to begin with. But when the “finished” floor tile ended up looking like this, the homeowner decided that there was probably definitely a problem:

If your tile installer can’t get it together to grout properly (by, for example, grouting right over the drain), then that’s a bad sign. If your tile installer uses unsanded grout for the shower floor, then that’s a worse sign. And if your tile installer can’t figure out how to clean unsanded grout from ceramic tiles? Well, that’s a quite bad sign. And finally, if your tile installer MAKES THE SHOWER FLOOR COMPLETELY FLAT, then don’t pay. Because you’ll need to pay someone else to clean up the mess.

At least the dope was in the end truthful about not knowing what they were doing. When at first sight of the completely flat shower floor the homeowner asked “So, ah, how is that going to drain with no slope at all?”, the dopey know-nothing contractor apparently immediately replied with a resigned “Well, it probably won’t.”

So at least the shower was never used in this condition. With no waterproofing at all for the shower base and no slope at all to the shower drains, even one use would have immediately resulted in at least hundreds (perhaps thousands) of dollars worth of cosmetic and structural water damage to the home since this particular shower was located on a second floor right above the ground floor livingroom. At a minimum, the homeowner would have had water dripping onto their entertainment center right away.

Not good.

An Expensive Lesson!

The homeowner had tried to save some money by getting a ‘contractor friend’ to install a large custom tile shower. The result was a useless unwaterproofed mess and a bunch of tile that’d have to be immediately ripped out and hauled to the dump.

This highlights the importance of not getting trapped into eventually paying a pound by trying to save a few pennies. In general, you actually do get the results you pay for when paying for contractors. If you want to go cut rate, be sure that the worst possible result will at least be only cosmetic.

In  other words, don’t cut corners when water is involved or you’re likely to end up all wet (waka waka).

Still Fixable? Fortunately, Most Definitely!

The good news is the know-nothing ‘contractor’ at least knew enough to use concrete backerboard for the walls. This would make it possible to do a somewhat creative fix to at least minimize the repair bill — remove the floor and just the first row of wall tiles to build a new proper base for re-tiling.

Although the shower wall tile wasn’t completely flush or straight, it was at least serviceable. At a minimum, shower wall tile just needs to stay on the wall and not be hung on drywall. And, keeping the existing wall tile would save the homeowner a bit of materials cost.

So what does a shower floor replacement process look like? Read on to see in “Shower Repair Rescue, Part DEUX“