In the past, movement accommodation joints in the substrate, more commonly known as expansion joints, had to be honored and this is still true. Additionally, interior installations subject to sunlight (heat) or moisture called for these joints to be placed a maximum of every 12 ft. in each direction, but they had to be in a straight line. Enter the new standard of the day: 12-by-24-in. rectangular tile—and we have a problem.
How can this tile be installed at the industry-recommended 33% offset and still provide for the expected movement? The method in the past was to cut the tile in a straight line, filling the joint with 100% silicone, urethane or polysulfide sealant which worked very effectively. Unfortunately the pattern was interrupted, leading many designers and consumers to resist this situation saying, “I don’t want my beautiful pattern to be destroyed by those ugly joints. Not on my watch!” When this scenario was followed, the installer was at a greater risk for the installation to fail, possibly resulting in tented tile.