Clean grout is well worth the effort for the value it adds to your clients’ perception of a clean home.
Cleaning dirty or discolored grout is a frustrating job, but doing it right adds immeasurable value to our reputation as cleaners. Grout in showers is exposed to soap scum, hard water deposits (or scale) and mold. Grout on floors is exposed to all types of funky grime. In both cases, cleaning the grout between tiles isn’t always straightforward because it often lies slightly below the level of the tile, requiring a separate scrubbing with or without a stronger cleaning solution. To help us do this right, let’s take a look what grout is.

What is Grout?

Grout is a mortar, a thick building material that hardens and is used in masonry or plastering. Grout binds tiles together and separates them a specific distance from each other. Grout also prevents the edges of tiles from getting damaged, prevents debris from getting caught in the crevices between the tiles, and provides a decorative accent. 

There are two common types of grout: sanded and unsanded. Sanded grout is typically used between standard ceramic tiles and is more durable than the finer unsanded grout you’ll usually see more with natural stone (e.g., granite, marble, and glass) floors and treatments, as well as tiled kitchen countertops.

Why is grout so hard to keep clean and white?

Grout is challenging because it is porous and absorbs water and soil. This makes it easy to stain and darken as spills are absorbed, soil is tracked in on shoes, or dust settles from the air; this porousness also makes it impossible to disinfect.

And because tile is most commonly used in the “wet” rooms of a home, it is constantly exposed to moisture, which, in the presence of organic material, like food residues in the kitchen and body oils and skin cells in the bathroom, promotes the growth of mold. This tempts most people to use harsh chemicals to clean the grout. 

If you are having a difficult time removing what seems to be an intractable stain, asking if a masonry or grout sealer was applied will help with your cleaning action plan. Sometimes it is obvious a colored grout sealer was applied in a shower or on a countertop because the grout lines look painted. Clear grout sealer may make the grout look unusually shiny. Often it isn’t obvious a sealer has been applied unless the grout wasn’t cleaned well before the sealer was applied.  

Strong cleaning chemicals, natural cleaners that are strong acids and bases, high temperatures from steam vapor cleaners, and vigorous scrubbing will wear off these grout and masonry sealers pretty quickly. If your client has sealed grout, using milder cleaning products might be your best option.

What is NOT recommended for cleaning grout?

While it is certainly satisfying to see grout restored to its former bright glory, when used regularly harsh products can harm the grout itself and the surrounding surfaces. The problems with harsh (often acidic) chemicals used to clean grout include: 

  • Damage to surrounding surfaces, including commercial and natural tiles
  • Severe etching of the grout causing it to become more porous, making the grout more susceptible to staining and possibly causing moisture damage to surrounding areas
  • Damage to natural stone such as marble, travertine and limestone. 

What are some best practices for cleaning grout?

When you clean a tile surface on a regular basis, it is best to choose a milder cleaning method and leave the more extreme methods for first time jobs with trained cleaning techs.

  1. Focus your method on the A in CHAT (see graphic). Gentle, consistent agitation with a scrub brush aids the removal of mold and soil. Avoid scrubbing too vigorously, which can erode the grout and destroy the grout’s integrity, causing problems with loosened tiles and moisture damage around or beneath the tiles.
  2. Test any chemical products (even homemade ones) for color safety. Use caution with colored grout. Many grout cleaners are designed to whiten the grout, but you don’t want to bleach out the intended color of the grout. Always read the labels of any grout cleaning product to check if it is safe to use on colored grout. Test any product you choose to use in an inconspicuous area, especially homemade cleaning products which have arbitrary recipes and concentrations.
  3. Wear your safety gear. Most cleaners work best with warm to hot water (the H in CHAT – see graphic). If you use hot water, remember to protect your hands. No matter what cleaning products you use, you will want to take proper precautions and wear rubber gloves, eye protection and work in a well-ventilated area.
  4. Start tough jobs with the mildest option and increase strength only as needed. Grout cleaners, whatever your choice, are usually best applied to dry grout so the solution can soak into the grout. Always read the label of any commercial products to be sure. Start with the mildest or most diluted solution and increase the strength of the solution as necessary to get the preferred result.

In Part 2 of “Don’t Pout about Dirty Grout,” I explore the lowest impact chemical options (sometimes called “green” or “natural” cleaning solutions) for cleaning and whitening grout as well as protective options for keeping grout clean longer between cleanings.

Janice Stewart is the owner of Castle Keepers of Charleston and driving force behind the development of the Modern Cleaning approach, Janice brings her scientific and healthcare background to inform the development of effective, safe, and healthy cleaning methods.