Why Tile Choice Is a Technical Decision
Tiles are frequently treated as a design element selected by the client and installed by the tradesperson. In practice, tile selection is a technical decision with compliance, longevity, and safety implications that the builder or tiler is responsible for understanding. The wrong tile in a wet area fails. The wrong adhesive on a heated floor lifts. A tile without the correct slip rating in a commercial bathroom creates liability. Getting tile specification right requires knowing what the available options are and what each is suited to.
Tile Types and Their Applications
Ceramic tiles are made from clay fired at lower temperatures and are typically glazed. Cost-effective and easy to cut, they suit indoor walls and low-traffic residential floors — bathrooms and kitchens where moisture exposure is moderate. Their higher porosity compared to porcelain makes them unsuitable for high-moisture or high-traffic applications without additional protection.
Porcelain tiles are fired at higher temperatures, producing a denser material that absorbs less than 0.5 percent of water. Available glazed or full-bodied (the colour running through the tile rather than just the surface), porcelain is the appropriate choice for high-traffic floors, commercial spaces, wet areas, and outdoor use. More difficult to cut and more expensive, but the durability and low maintenance are appropriate for demanding applications.
Natural stone — marble, granite, slate, limestone, travertine — offers premium aesthetics and genuine durability when sealed correctly. The variability in quality within stone types, the maintenance requirements, and the higher installation cost make it suitable for high-end residential and commercial applications where the investment is justified by the outcome sought.
Mosaic tiles (glass, stone, or ceramic on mesh sheets) allow installation on curved surfaces and provide decorative flexibility for splashbacks, shower niches, and pool surrounds. Time-consuming to install; grout lines require more cleaning attention.
Cement tiles are gaining traction in boutique commercial settings for their patterned character. Porous and requiring sealing; not suitable for environments where staining is a concern without thorough sealing maintenance.
Technical Considerations
Slip ratings: The New Zealand Building Code sets minimum slip resistance requirements by environment and use. Wet areas, commercial kitchens, pool surrounds, and entrance areas all have specific requirements. Check the R-rating or P-rating for any tile being specified for a slip-sensitive application — do not assume a tile is compliant because it looks textured.
Water absorption: Porcelain’s sub-0.5 percent absorption makes it suitable for outdoor use in freeze-thaw conditions. Ceramic and stone tiles in wet or outdoor applications require waterproof membranes and compatible sealants.
Substrate preparation: The substrate must be flat, stable, clean, and dry. Large-format tiles demand a higher degree of substrate flatness than smaller formats — even slight undulation produces lippage that is aesthetically unacceptable and creates a trip hazard. Do not rush substrate preparation.
Adhesives and grouts: Flexible adhesives are required for underfloor heating applications and timber substrates. Epoxy grout suits commercial kitchens and high-moisture environments. Using standard adhesive on a heated floor is a callbacks waiting to happen.
Movement joints: Tiled surfaces expand and contract. Without movement joints at appropriate intervals, tiles crack or lift. Movement joints must be correctly sized, filled with flexible sealant, and compliant with industry standards — they cannot be grouted over.
