What type of grout should I use?

February 23, 2009

Some simple tips for grouting

Q:I am going to be installing a new ceramic-tile floor in my bathroom and I am looking for some advice for when it comes time to grout.

What type of grout should I use (i.e. sanded or unsanded)? Any tips for applying the grout would be helpful since last time I installed tile it didn't turn out as well as I would have liked.

-- Harold, Maple Ridge

A: Becoming a good tile-setter is possible if you follow some of the simple techniques that are used by the pros. For floor-tile installations, purchase a powdered formula "sanded" grout. Typically, the sanded grouts are used for wider grout joints (1/8-inch to 1/4-inch joints), and "unsanded" grout would be used for wall-tile installations (grout joints of less than 1/8-inch widths.)

To begin, clean the surface of all debris and any protruding bits of bonding material. The cement in grouting material is what makes it hard and takes a reasonable time to harden. If the grout dries too fast, it might not be as hard as it should be.

To improve the resulting grout, use a damp sponge or spray bottle to dampen (but not soak) the joints between the tiles an hour or so before applying the grout. To mix the grout; add water to the powder and mix to a consistency of peanut butter (do not make it too runny or over mix since this can entrap air bubbles). Let sit for about five minutes, and then lightly stir.

Apply the grout in the joints with a rubber-faced grouting trowel or float.

Let stand for about 15 minutes. Using a spray bottle, spray a misting of water on the entire surface. Immediately use the float trowel and repeat the squeegee process to further remove the surface grout and smooth out the joints.

Let the grout sit about 30 minutes, then use a damp (not wet) sponge and lightly wipe the surface of the tile. Do not use a circular motion; use diagonal strokes, being careful not to disturb the grout lines. The fine dust residual can be removed the next day when the grout is dry.

Allow 12-hours before further washing or any foot traffic. All cement-based grouts should be sealed with a solvent-based sealer to retain their appearance and reduce their cleaning. Grout must cure for a minimum of one week before applying sealer.