Before choosing the grout for your tile installation, think about what kind of appearance you want the surface to have. For example, if the grout you choose is similar in color to the tile, the surface will appear very uniform. Conversely, if you contrast the color of the grout with the tile, it will give the surface a geometric feel. The best idea is to obtain some grout samples before deciding and test them out with a few tiles.

Also keep in mind that the width of your grout lines, which can be anywhere from 1/16 to 1/2 inch, will affect the surface’s look. The wider the grout lines and the more contrasting the color of grout with the tile, the more the tile laying must be precise. If, however, you have chosen, say, large saltillo tiles for a floor, slightly irregular grout lines will only add to the rustic effect of the tiles themselves. This is all the more reason it is important to obtain some grout samples beforehand and experiment not just with colors but with the layout.

For lines under 1/8 inch, use unsanded grout; for greater than 1/8 inch, sanded grout. If the grout is polymer- or latex-based, mix it with water; if not, mix it with liquid latex. When the grout has completely set up—and certainly within two weeks—seal it or it can stain. If the installation is in a location where the risk of staining is a likelihood, such as a kitchen countertop, ask your tile dealer about whether or not you can use epoxy grout with the type of tile you have chosen.