The grouting between ceramic tiles, particularly those in the bathroom and kitchen, require regular care in order to keep them looking new and limit the spread of mould and mildew, which can be recognized by the presence of black spots or streaks.

Routine cleaning

The secret to long-lasting grout joints: washing, brushing and rinsing. If you choose the right product and use the right technique, you will have to do a routine cleaning only every two or three weeks, or even less often if the tiles have not seen intensive use or been exposed to substances likely to leave behind a dirty film.

Avoid using all-purpose cleansers whenever possible; instead, use products designed specifically for cleaning grout joints. The best product is a neutral cleaner, which is one that has a pH level of 7 (neither acidic nor alkaline). Such a product’s wetting and washing agents emulsify grease, soap residue and oil, thus removing any dirt that is encrusted on the grout or stuck to its surface. This type of mild cleaner does not damage the grout, sealant or tile finish. As well, use a biodegradable product that has been certified by a recognized organization and that is not harmful to human health.

If the product needs to be diluted with water, make sure you always follow the directions on the label. Some products may need to be diluted more than others, depending on the type of cleaning required (light or heavy). Before using the cleaner, be sure to read and measure!

Use a nylon brush with bristles that are soft enough to prevent scratching the tile surface, but stiff enough to dislodge dirt. This type of brush is more effective than a sponge or cloth because it can more efficiently reach the grout, which is often below the level of the surrounding tiles.

Once you have poured the cleaning solution on to the surface, wait for the amount of time specified in the instructions and scrub the joints with the nylon brush. This is essential, since grout is porous and tends to absorb and retain dirt on its surface. As well, a helpful hint: always test the cleaner on an inconspicuous section of the tiling before applying it to the entire surface.

Once you have finished scrubbing, always remember to rinse the surface with clean, lukewarm water. This is the key to effective cleaning: if you do not thoroughly rinse the grout, the dirt will mix with the soap residue and cover your grout, and you will have to start all over! To make sure that you have properly rinsed the surface, check to see if the tiles are sticky to the touch. If they are, rinse the surface again to eliminate any soap residue.

Stained grout

Even after a thorough routine cleaning, is the grout still stained? If the tiling has not been cleaned for some time, it is quite possible that a substance, such as rust, has marked your grout and is proving very difficult to remove. Before you start thinking about redoing the joints, you can try a more intense cleaning with one of the following types of products:

  • More powerful products: these should be used with caution, as they may be hazardous to the person using them, the tiling (tiles, grout, etc.) and the finish;
  • Acidic products: these should be used only as a last resort. In general, these products are not intended for household use, and it is better to let a specialized company handle them.

What should you do if, despite everything, your grout is still stained and cannot be salvaged? You have two choices:

  • Redo the grouting: this is a delicate operation in which you remove at least 2/3 of the grout using a scraper or grinder, and then reapply;
  • Apply a colorant-sealant over the existing grout.

Sealing the grout

Are you doing renovations or building a house? To make it easier to maintain tile joints and protect the grout, a sealant may be applied when you are laying the tiles. However, this is not a permanent solution. A new layer of sealant should be applied once water has stopped beading on the surface and the grout becomes darker when it is wet. This is the best way to maximize the durability of the joints, in terms of both appearance and waterproofing.

Special thanks to François Croteau, Technical Consultant at MAPEI, for contributing to this article.