No Drill Holes: A Cautionary Tale of a Shower Installation Gone Wrong

Many hours of planning and material selection go into the process of creating a beautiful stall shower and adjoining bathroom. Equally important is the selection of the tile contractor who utilizes Qualified Labor to bring the client’s dreams to fruition. 

The TCNA Handbook and ANSI Specifications provide a clear course of action for the installer.  The Tile Council of North America (TCNA) Handbook method B415 STONE, a water-in and water-out system, offers guidance for the fabrication of the shower receptor, including sloped fill (pre-slope), an approved shower pan membrane, and weep hole protection to effectively evacuate the water from the shower receptor assembly, especially when the shower floor will be natural stone. 

Due to the barrier-free design of this shower, the general contractor provided a double recess for the shower pan. The first recess accommodated the sloped fill under the shower pan membrane, while the second recess allowed the tile contractor to match the height of the adjacent heated bathroom floor. This feature caused the mortar bed to be 3-1/4” which was not a challenge to these tile mechanics.  

The installation went flawlessly thanks to the meticulous planning of the tile contractor, who has completed many similar projects. The job was completed, and the glass contractor was ready to begin. The tile contractor made certain that the glass contractor understood the necessity of carefully placed holes in the tile assembly as well as the depth of the anchor holes.  

However, when the glass contractor arrived on site, the drilling requirements that had previously been provided were ignored entirely.  

In the image, you can see three of the four mounting brackets for the glass panels, which each required one screw. The glass installer wanted to be certain that the glass would not move or cause problems and therefore decided to drill though the marble tile, thin set mortar, secondary waterproofing, the 3-1/4” mortar bed, the shower pan membrane, the sloped fill, and finally into something solid – the plywood subfloor. To do this, the glass installer used six-inch stainless-steel screws. Also, the shower door included a pivot hinge which, in and of itself, can pose significant issues in most tile installations by compromising the waterproofing. But in this case, the pivot pin was significantly shorter than the mortar bed and was not a problem.      

It took several months before four leaks were discovered. The tile contractor had to remove most of the layers mentioned above to get to the shower pan membrane and make the membrane manufacturer’s recommended repairs. 

The ironic part of this installation was that the hot water towel heater, seen on the left of the glass enclosure, included sixteen chrome screws to anchor the device to the marble floor along with two hot water pipe penetrations, all of which were successfully installed by the plumber based on instructions from the tile contractor. 

ANSI A108.02-5.1 Penetrations in completed tile assembly states: “Penetrations into waterproofed tile assemblies should be avoided, whenever possible. If waterproofed tile assemblies must be penetrated, it is recommended that penetrations be made away for the stream of water (e.g. water from a shower head). The party responsible for the penetration is also responsible for the treatment and/or repair. Penetrations into waterproofed assemblies must be treated and/or repaired such that they remain waterproof.”   

Given this language, it is clear the tile contractor was not responsible for the repairs. Still, Woody Sanders of D. W. Sanders and his installers, all Certified Tile Installers, made these repairs at his expense to satisfy his customers and make it right.