Damaged and Leaking Shower

Posted: July 12, 2010 in Ceramic Tile & Stone, Projects, Showers & Tubs By: Kevin Trevathan

This is a project that started with a conventional shower in a home in Northwest Arkansas. The shower was built improperly with sub-standard methods. The result was that the shower leaked from the first day it was used, and continued to leak for the next four years until water began dripping through the basement ceiling. The worst thing about a leaking shower is that it is almost impossible to repair and requires extensive demolition.

Let’s start with the shower as I found it: By pulling off the trim ring on the valve, I can see that the backer for the tile is actually moisture-resistant green board which is not a suitable backer in a shower.

I can also see that under the marble threshold there is significant mold growth. This indicates that there is water trapped in the dam, and it’s almost a given that the framing is damaged and swelled. The homeowner showed me the ceiling inside a basement closet where water comes through after the shower is used. I begin the demolition by taking out the floor and immediately I find that the liner is lying flat on the floor.

This is a very common mistake with the installation of conventional tile showers. The liner is actually cut at a height that is below the dam, and it’s also cut at the corners where the door jamb meets the dam. As a result, the framing is damaged to the point that this entire wall must be cut out and replaced.

Grout is not waterproof, so a significant amount of water has left the area of the shower over the past four years. The bottom 16″ of the studs are saturated, but fortunately not ruined. I can sister them with a 4′ 2×4 to give me something stronger to work with. The wall at the back of this shower is a common wall with a fiberglass shower in another bedroom. While nothing in the other bathroom was damaged, if there had been a bedroom or closet on the other side of this wall, the leak would have probably been found much sooner.

lack of thinset

I complete the demolition of the entire shower down to the studs, including the removal of the insulation that was wet up to about three feet. One tile that was near the ceiling was only held in place by the grout that was around it. There was no thinset on the tile or wall. I directed a fan toward the shower and let it dry out overnight.

The next day after everything is dried out, I start by adding a layer of 3/4″ plywood to the floor. While the original floor was not rotted, it was wet and had turned black in the area where the leaking was worse. The extra layer is insurance in case the subfloor has turned soft from the years of being saturated. A strong subfloor is absolutely necessary for the weight of the materials that will be installed here. I also install a corner bench in the shower which the homeowners had wanted when the house was originally built. The top of the bench constructed with 2×4′s and a layer of plywood for the seat. I install new drywall on the seat and throughout the entire shower. Drywall is the preferred substrate for Kerdi waterproofing membrane which will be installed here.

When demolishing this leaking shower, I took careful measurements of the door opening. When reconstructing the shower (which including re-framing the two front walls), I made sure that the width of the door opening was the same as before. This allowed me to use the same glass door and saved the customer several hundred dollars.

Now I install the mud floor, using several hundred pounds of sand topping mix (remember the new layer of subfloor?) along with the patented Kerdi drain.

mud floor shower bench

After the mud floor has dried overnight I prepare to install the Kerdi membrane. I carefully took measurements of the dimensions of the shower and pre-cut the Kerdi so I can quickly install it in one day.
I mix about 25 lbs. of dry-set mortar (Mapei Megabond in this case) to install Kerdi. Thinset has to be much wetter to install Kerdi. I’ve also found that lightly dampening the drywall with a sponge keeps the thinset from drying out before I can get the Kerdi on the wall. I install Kerdi on the floor first, then work my way up the bench and corners, followed by the walls. The tile is a special order and won’t be in for a couple of days, but that will allow the Kerdi to fully dry before I start tiling. In about four days this customer will have a fully waterproofed shower that will last for many years, and (most importantly) won’t leak!

kerdi bench corners kerdi walls

Since this shower was a little larger than most, and required complete demolition, re-framing, and a complete installation, the start-to-finish time was a little over two weeks. Most showers do not take this long to complete, but a leaking shower always requires more time, and is consequently more expensive to rebuild.

In the following pictures, the tile has been installed and grouted. The tile that was originally installed in the bathroom was not available any more, so the customer picked out a complimentary tile. The customer also chose a pebble stone for the floor and accent.

Replaced shower door Completed shower walls

Pebbles come in a variety of shapes and styles, and this particular pebble is rounded on top. If you choose a pebble for your shower floor, it’s a good idea to lay some out on the floor and walk on them in your bare feet to see how it will feel in the shower. Not everyone will like the feeling of walking on pebbles, and you’ll want to find that out before you go to the expense of installing them in your shower.

In addition to being installed on the floor, a row of pebbles was installed on top of the fourth row of tiles as an accent, and on the front of the shower curb. Because the pebbles require much more grout, several coats of sealer are recommended to make cleaning easier. Trevathan Floors recommends a simple cleaning method for all tile showers: after each use, hand-dry the tile with a towel. This cleaning method requires no chemicals or cleaners and allows your shower to dry much faster. It also wipes away any soap scum and mineral deposits left on the surface of the tile and grout. A shower that is hand-dried after each use will require no other maintenance under normal conditions.

Pebble floor and Better Bench Pebble floor of finished shower

Because of the size of this shower, a number of soap dishes were installed in the corners. Trevathan Floors can also install recessed soap dishes in your shower for a slight additional cost. Recessed soap dishes are more valuable in a smaller shower where space is limited. The same can be said for benches, like the one in this shower. This bench is built up from the floor with dimensional lumber and drywall, and takes up a small amount of floor space. A Better Bench, which is attached to the walls, will free up that floor space in a smaller shower. Look for a Better Bench and recessed soap dishes in upcoming projects on this site.

If you suspect your shower has been improperly built or is leaking, call Trevathan Floors for a free assessment and estimate.

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