The topic of spot bonding floor tile was covered in CTEF Tile Tip about a year ago, and one would think the installers that utilize this technique would heed the warning and stop installing tile in this way. Unfortunately, that has not happened.
This problem continues to be high on the list of questions received by the CTEF offices when things go wrong. Too many installers continue to spot bond their floor tile by placing a dollop of mortar (about the size of a golf ball) on each corner with one in the middle of the back of the tile. This process, commonly known as “five spotting,” fails almost every time because the majority of the tile is not supported or bonded by the mortar (see attached photo).