Red Seal Tilesetter Practice Exam

Which substrate is not recommended for tile installation?

1. Concrete

2. Stucco

3. Plywood

4. Plaster

The correct answer is: Plywood

Plywood is not recommended for tile installation due to its susceptibility to moisture and instability. When exposed to water or high humidity, plywood can warp, swell, or contract, which compromises the integrity of the tile installation. Tiles adhered to a moving surface can crack or come loose as the plywood shifts, leading to costly repairs. Moreover, industry standards and practices generally favor substrates that offer a rigid, stable platform for tile, which plywood does not provide in variable conditions. Alternatives such as cement backer board or a reinforced concrete surface are preferred in tile installations because they provide the strength and stability necessary to accommodate the weight of tiles and the potential movement that can occur over time. Using unsuitable substrates, like plywood, can lead to failures in the tiling system, resulting in unsightly and unsafe conditions for the finished product.