Explain the difference between expansion joints and control joints in tile installations.

• A. They are the same thing
• B. Control joints absorb movement; expansion joints provide crack control
• C. Expansion joints absorb movement; control joints provide pre-planned crack control in the substrate, typically aligning with expansion joints
• D. Expansion joints only for walls; control joints only for floors

Answer: (C)

Movement joints in tile work separate sections to let the structure move without transferring stress to the tile, while crack-control joints create a planned break line in the substrate to keep cracks from propagating into the tile field. Expansion joints absorb and accommodate dimensional changes from temperature, moisture, and movement, and they’re typically filled with a flexible material so the joint can flex without pulling on the tile. Control joints, by contrast, are pre-planned joints cut into the substrate to direct where cracking will occur, usually aligning with the expansion joints so any cracks fall along a joint line rather than through the tiles. This alignment helps keep the tile pattern intact and reduces unsightly cracks.