The ceramic tile industry has grown substantially in recent years and a big percentage of the growth is seen in exterior installations. This can be for multiple reasons, including a cleaner, more contemporary look, better mortars and grouts, and large-format and gauged porcelain tiles. Large-format and gauged porcelain tiles today really lend themselves to be an exterior cladding material competing with wood siding, stucco, EIFS, glass and aluminum composite panels because this installation has a flatter appearance, a large variety of sizes, as well as ease of maintenance and cleanability. There are a lot of important decisions that must made when selecting tile for exteriors.
When selecting for walls, properly prepared and building code-approved substrates are essential. Common exterior substrates include masonry, concrete, mortar bed and cement backer board over framing. There is also existing cement stucco over a cement basecoat, etc. The current ICC building code in Chapter 14, under paragraph 1405.10.2 Exterior Adhered Masonry Veneers-Porcelain Tile, states: “Porcelain tile shall be adhered to an approved backing system.” The ICC building code also states in Chapter 14 that adhered units shall not exceed 5/8-inch (15.8 mm) thickness and 24 inches (610 mm) in any face dimension nor more than 3 square feet (0.28 m2) in total face area and shall not weigh more than 9 pounds psf (0.43 kN/m2). I am aware of a successful effort to get these sizes in the building code updated in future printing and adoption of the ICC. This effort will allow for the size of tile in the case of Gauged Porcelain Tile (GPT) to be up to five times larger. Until the building code is changed, however, the project owner, builder, architect or engineer should seek local code approval for the use of a GPT and/or larger format porcelain tile finish material for the exterior veneer.