Tile shower floors are nice, unless they are leaking! This is the case for a Nashville homeowner that asked me to repair their shower floor.
This was an old shower that was likely 40-50 years old. The way of installing a shower back then (and still today in some cases) was to first install a waterproof membrane that goes around 8″ up the walls all the way around. Then, a sloped bed of mortar or ‘mud’ is installed before tiling the floor. A specific type of drain is used that makes a seal with the membrane.
Many people have the misconception that grout is waterproof. This is not true. Most of the water is deflected and just goes down the drain, however, a small amount is absorbed through the grout and mortar. When it gets to the waterproof membrane the water is funneled to the drain and through tiny ‘weep holes’ that send the water down the drain.
My guess is that the weep holes were clogged with this shower. This meant that the mortar bed was saturated with water and it was full enough that it was dripping over the top of the membrane around the sides. I saw evidence of this when I started removing the bottom tiles and water started pouring out from behind.
TEAR IT OUT
The homeowners didn’t want to replace the entire shower and I can’t blame them. This is expensive work. Instead I would just be tearing out the bottom few rows and installing a new waterproofing system called Kerdi from Schluter Systems. First, I had to get dirty.
Getting started was easy because many of the tiles were loose anyway and came right off. After that I went around with my hammer and a flat bar and busted out the tile. Of course, I was careful not to damage the tile above that I wanted to keep.
The wall tiles were set on a mortar bed containing wire mesh for strength. Below that was the black shower membrane that had to go. It all chipped away fairly easily exposing the thick mortar bed under the floor of the shower. This mortar didn’t contain any mesh and broke apart into pieces that I could just scoop up and dispose of.
Finally, I had worked my way down to the subfloor that was wet and needed to be cut out. It wasn’t long before I was looking into the basement and ready to start putting it all back together.
