As I travel around the country, I continue to hear the same statement no matter where I go. The statement goes something like: “The general contractor won’t pay for prep work” or the statement from the GC is “Just get it done, it will be fine.”

Well in most cases, it will not be fine and neither the owner nor the general contractor will accept the completed work. Surface prep, whether for the wall or floor, is critical to the completed job being acceptable to the end user. If the substrate is not flat, the finished surface will mirror the irregular substrate—which is especially true when ceramic tile is installed over concrete block walls.

The attached photo illustrates the problem. The GC would not pay the installer to properly “fix” the concrete block wall and was told to just use more thin-set mortar to build up the low spots. This was poor advice, which unfortunately the tile installer followed.

In this case, the job called for a 4" by 12" subway tile to be installed on the wall. This installation would fall under the ANSI A108.02- requirement which states: “For tile with all edges shorter than 15in. (0.38m), the maximum allowable variation is no more than 1/4" in 10' (6 mm in 3 m) and no more than 1/16" in 1' (1.6 mm in 0.3m) from the required plane, when measured from the high points in the surface.”

To further complicate the problem, “wall wash” lighting was added after the tile had been installed. This type of lighting is installed in or on the ceiling, directly above the wall. The cascading light accentuates any irregularities in the wall surface. In this job, prior to the lighting being installed, tile work was acceptable. However, after the lighting was installed, the job was rejected by the owner and general contractor.

There are two lessons to be learned from this job. Always insist that the substrate is tile-ready. If not, send an RFI (request for information) to the architect and general contractor. This puts them on notice (in writing) that there is a problem and that work will not begin until the surface is within ANSI tolerances. If they reply (in writing) and instruct the installer to begin work, obtain a written and signed document which specifically tells the installer to start working without the appropriate corrections.

The second lesson is the permanent lighting must be installed before the tile is installed. Without this lighting, it is practically impossible for the installer to realize there may be an issue with his or her work. Again, notify the GC (in writing) that work will begin only after the permanent lighting is installed.

Stand your ground or be prepared to redo the work and/or risk not being paid for your efforts.