Volume 28/Number 6; September 1/8, 2014
(Editor’s note: This is the ninth of a 10-part series on introducing flooring retailers to stone and the opportunities the category presents.)
Sponsored by Emser Tile
From ancient monuments like the pyramids in Egypt to the great civilizations of India and China, natural stone has been an important part of architecture throughout history, lasting for hundreds of years.
These days, natural stone is becoming a more common option for consumers who want to beautify their homes with this distinctly unique product.
But before any of that can happen, the stone must be installed properly. And that work is best left for the professionals, as natural stone is heavy, arduous work, extremely exacting and requires training and special tools.
Bob Baldocchi, director of marketing and sales support at Emser Tile, said preparation is vitally important when it comes to installing natural stone. “Prior to install, the mechanics should lay the material out to get a sense of range and looks,” he explained. “Make sure everyone is comfortable with what they are seeing.”
This step is important because there is tremendous variation in natural stone. The samples the consumer sees in a retail showroom won’t be the same as what she gets in her home because the colors and mineral veining will vary. “You really need to inspect the flooring before putting it down,” Baldocchi noted.
Up next for installers is preparing the substrate. “You want to make sure you are starting with a substrate that is appropriate for the material you are laying down.”
Installers apply a thinset mortar—Baldocchi said the right type of mortar is critical—directly to a cement subfloor and lay the tile. Wood subfloors require a CBU (cement backer unit) for support and to provide a moisture barrier.
The substrate material may move. This can occur when water penetrates the grout, or when freezing and thawing causes the tile to crack, rise or chip. To help prevent this, some installers use Ditra, a brand of underlayment that allows for slight movement of the substrate without damaging the floor.
Stone tiles install slightly differently than ceramic or porcelain tiles because care needs to be taken for the natural variations in the stone. Stone tiles may have fissures that vary in thickness from piece to piece. To lay these tiles properly, a good foundation and layout is required.
The professional installer will measure the area and snap chalk lines for an accurate layout. Some pieces will need to be cut to fit a particular shape of the room. These are measured, marked and set aside for hand cutting. The installer then uses a wet saw with a 10-inch diamond blade to customize the stone. Freshly cut edges are smoothed by hand with a smoothing stone.
Baldocchi recommends waterproof membranes in wet areas. Many waterproofing membranes feature anti-microbial protection to help fight off stain-causing mold and mildew. As well, waterproofing membranes help prevent the occurrence of poor indoor air quality.
Stone floors are rarely precisely level, Baldocchi said, but quality installers check to ensure everything is as level as possible as they move along, setting the tiles or stones. To compensate for the varying thickness of the stone, they adjust the amount of thinset mortar.
After the floor is laid and the thinset mortar has fully cured, the installer fills the joints between the tiles with grout. (Un-sanded grout is most commonly used.) A grout mixture is spread over the tiled area to fill in the joints (the grout curing process takes about 48 hours). Installers then wipe off the excess with a sponge.