The surface of grout is porous and as a result it can get so dirty it becomes impossible to clean it successfully, even our most powerful cleaners struggle if it gets to this stage. If you get to this point you could use the flat end of a screwdriver to scrape out the grout and re-grout the whole floor to ensure a consistent colour, naturally this is arduous work and can be time consuming however there is a second option and that is to apply a Grout Colourant instead. The grout colouring products we use not only change the colour but it also provides a protective barrier that seals the grout as well ensuring it keeps it appearance well into the future.
Preparing the Grout
Before applying a Grout Colour it’s important to ensure the grout is clean of grease and any sealer that may have been applied to the adjacent tile; Tile Doctor Pro-Clean is a strong alkaline cleaner that’s good for this purpose, for best results you should allow the cleaner to dwell for a while and then get into the grout joints by hand with a stiff brush. Last step is to rinse the floor down with clean water to remove any chemical that might upset the colourant, I recommend the use of a wet vacuum at this point to remove liquids from the floor.
Applying the Grout Colour
Once the grout has dried you can start applying the colourant which is a relatively straightforward process of squeezing the product onto a toothbrush and running it onto the grout. Don’t be tempted to use an old toothbrush for this purpose as it may contaminate the colourant leading to discolouration in the finish. The product sets in a couple of hours so I was able to do the whole floor in a day.
Source: Grout Colouring in Chorley, Lancashire