Tips for Laying Stone
Laying stone is different than laying ceramic, and the differences could bite you if you don't know about them.
I've installed enough ceramic tile to feel fairly confident with the basic techniques of lay-out, cutting and setting. But I've never worked with stone, and I'd like to give it a shot when we remodel our bathroom. Are stone installation techniques much different than those for ceramic tile?
— Kathy Silverwood, Southbury, Conn.
Joe Ferrante replies: They're similar in many respects, but if you don't pay attention to the differences you can really mess up a job.
For one thing, you can't score and snap stone the way you can with ceramic tile; you'll definately need to rent a wet saw. Also there's going to be greater variation in sizes, colors and thicknesses, so you have to work a lot by eye and feel. For instance, you won't be able to rely on those X-shaped plastic spacers to keep everything even, unless you use "gauged" stone cut to a uniform thickness and size.
Stone is more porous than ceramic tile, and you have to be careful about what it touches. Some light-colored stone will absorb the gray color from ordinary thinset adhesive, so it's best to always use a white thinset with stone. Grout, too, can stain some stone. Before you grout, seal the surface with a penetrating sealer, sometimes called an impregnator. Sealing also makes grout cleanup easier.
Joe Ferrante is a tiling contractor in Massachusetts who has worked on many This Old House TV projects.