Can I Install Porcelain Tiles Directly on a Clean Concrete Slab?

Porcelain Tiles

• Porcelain tiles are made from specially formulated white clays that are fired at high temperature, producing a surface that is exceptionally durable and wear-resistant. Porcelain tiles are colored by dying the clay itself rather than applying a surface glaze, making chips and other damage much less noticeable. The lack of glaze also allows for much more intricate patterns to be machined into the tile surface, making porcelain suitable for a wide range of applications. Porcelain tiles are denser and less porous than conventional ceramic flooring materials as well as less brittle.

Adhesives and Substrates

• Porcelain tiles are installed similarly to most ceramic flooring materials, although their increased density requires the use of stronger latex-reinforced mortars. Porcelain tile bonds well to a variety of substrate materials, including plywood, concrete, mortar beds, plaster and cement backer boards. Latex-reinforced thinset adhesive mortars provide the best bond for residential applications and are widely available at home and garden centers. Thickset mortars offer good results but are better suited for professional installation as creating a smooth and level finish requires some experience.

Spacing and Layout

• Lay out porcelain tile projects as you would any other floor tile installation, beginning with pattern selection. Basic grids are the easiest and most practical for most applications. Snap chalk lines across the room in a grid, crossing in the center. The size of the interval depends upon the size of the tile; generally this is the width of the tile plus the grout joint. Lay the tiles out with plastic spacers to ensure clean lines and even grout joints. Mix the thinset mortar according to the manufacturer's instructions, and work it onto the surface of the concrete slab in small sections, no more than 10 feet at a time. Mortar thickness and trowel size vary according to the type of tile being installed.

Installation and Grouting

• Apply a thin coat of mortar to the back of the porcelain tile, and set it in place using a slight twisting motion. Ensure all tiles are level, and remove any excess mortar with a damp sponge. Cut any oddly-shaped pieces using a wet-saw. Porcelain tile should be left to cure for 24 hours after installation before grouting. Grout the tiles by spreading a generous amount of product over the tile surface with a grout float, and hold it at a 45-degree angle to spread it into the joints. Let the grout sit for a few minutes before cleaning off the excess with a damp sponge.