You Make the Call!
With a few tiles removed, we see what is beneath, a white powdery substance we all recognize when a pH test is performed (Photo 3). A very high 12-13 pH level is evident, and what's puzzling is "Where's the adhesive?" The adhesive has literally disappeared. Well, if adhesive was used, and we know some had to be, there has to be a residual trail somewhere. At this point, the amount used at the time of installation may be very hard to determine, right? But wait a minute, what about the telegraphing trowel ridges? Are they ridges from the glue that has disappeared? At this point, we ask a lot more questions, like who or what was used to level the substrate prior to the installation?