Tile tenting is when floor tiles have lifted, popped or buckled from their originally installed position. Tenting tiles occur when there have been changes in the environment or circumstantial to their initial installation. Movement in substrates e.g: concrete foundations, expand and contract with thermal conditions. A tiled floor system consists of layers of concrete, adhesive and then the tiled surface. Concrete moves differently to floor tiles. The substrate remains cooler than the tiles because it lays beneath the flooring.
Tile tenting can occur when the tiled surface is exposed to thermal conditions like sunlight, fireplaces or heaters. This can cause the tiles to be at different temperatures to that of the concrete foundations. The differences in temperatures may cause movement in opposite directions, causing stress on the tiles and grout joints. Inadequate room for movement, (no expansion lines placed throughout the tiled surface) may cause perimeter stresses and pressure build up. Pressure can cause tiles to tent, lift, pop, buckle and possibly let go altogether.
In a tenting failure, the tiles usually de-bond leaving the adhesive on the substrate. Sometimes this can be misinterpreted as a sign of a poor quality adhesive. Mostly, it is actually a sign of a good adhesive. Concrete and adhesive typically bond well together because they are made of similar cement based products. The bond between tile and adhesive is slightly weaker. The point of failure will occur at the weakest point. Another common failure is when the adhesive comes clean of the substrate and remains on the tile. This indicates poor surface preparation (i.e. tiling onto a dusty floor and inadequate priming of substrate).