Tile grout doesn't last forever. Long before it begins to physically deteriorate, tile grout will become discolored and unattractive. While this is an inevitable part of having tile flooring, walls, backsplashes, or counters, few homeowners ever want this or want to deal with it.
Grout discoloration happens because of mold and mildew, as well as dirt that imperceptibly collects in the tile seams over time. No matter how religiously you seal the grout and no matter how much you scrub the grout, you are bound to end up with dingy, discolored grout. Short of installing new tile, it is possible to change grout color in two ways. Either you can remove and replace the grout with colored grout or you can apply a colorant to your existing grout.
Change Grout Color by Replacing Grout
The most thorough and complete solution is to remove the grout and install new, colored grout. In small areas, such as backsplashes and tub or shower surrounds, this project can be less difficult than one might imagine. If the grout is crumbling or otherwise physically in poor shape, you gain the added benefit of all-new grout that keeps the cement board and studs behind the tile dry and in good shape.
Several tools can help you remove the grout with minimal effort. An electric multi-tool fitted with a tile blade can chew away the soft grout while preserving the harder tile edges. Manual screwdrivers and utility knives complete the task. A shop vacuum can suck out all remaining grout particles between the tiles.
Some grout comes factory-colored, though the range of in-stock colors is limited. These tend to be variations of gray, brown, or white. Pre-colored grout in a wider range of colors can be specially ordered. Another option is to add powdered or liquid dyes to a base grout. This broadens the palette of available grout colors to include variations of blue and red.
Change Existing Grout Color With a Colorant
Most homeowners would like to avoid removing grout if possible. One way to bypass the work and mess is to preserve the grout but change the color. Grout can be colored with dyes after it has been installed. You will particularly want to do this if the grout is stable and solid.
Grout's porous nature becomes a plus when you apply a grout colorant because this allows the color to quickly soak in and for the color to remain intact for a long time. To distinguish them from colorants that are added to wet grout, these retroactive grout colorants go by various names such as grout refresher, grout renewer, and grout reviver. Grout colorants rely on three factors for success: porous grout, glazed tile surfaces, and a steady hand. The greater the difference between the grout's porosity and the tile's resistance to grout colorant, the more successful this project will be.
Grid the Work Area
When applying grout colorant, you will be using either a special grout brush or a pen loaded with grout dye. Products such as Aquamix Grout Colorant, if they lap over onto the tile surface, can be scrubbed off of the tile face as long as two hours later with a nylon-faced sponge, provided the tile is well-glazed.
Tile professionals uniformly recommend gridding off a work area, coloring that section, and then stopping for the morning or even for the whole day. During the next session, grid off another section and work on that. You can grid off the work area with blue painter's tape, as it is easily removable and will not leave a tacky adhesive residue.
Not All Grout Can Be Colored
For the most part, you will find sanded or unsanded grout lines in your tile, but not always. The grout needs to be receptive to color. Sometimes you will find natural stone countertops where the tile seams were filled with silicone or other polymeric materials that will not be receptive to the colorant. Any type of seam that easily sheds water will not be appropriate for grout coloring.
Color Your Grout to a Darker Color
As with painting a wall, darker colors generally fare better than lighter colors since they cover up stains well. For floor tile grout, one trick to minimize your cleaning efforts for years to come is to choose a grout color that resembles the soil in your area. Regional differences can affect your choice of grout colorant. For example, in desert regions, Aquamix's Buff or even Linen White would most closely approximate the light-colored soils found in those areas. In the red clay regions of the southern United States, Wheat, Smoke, or Cinnamon may be more appropriate.
Be careful, though, of setting up a color contrast that is too dramatic. Black grout against white tile would create a grid-like appearance that some homeowners may find unpleasant.