Grout is used to fill the spaces between tiles on a wall, floor or countertop. Similar to mortar, grout begins as a powder and is mixed with water to form a thick paste. The paste is applied to the tile and allowed to dry, filling in the spaces and creating a waterproof seal around the tiles. Grout can be dyed to any colour, either before or after application.
Why Dye Grout
The main reasons for dyeing grout include custom colour matching and covering up stains or errors. If the original grout colour you have chosen doesn't look right with your tile, dyeing it a different colour will salvage the project without removing the grout entirely. If you have chosen a custom tile and want a specific colour of grout to go with it, you can dye a light-coloured grout to whatever tint you need.
Grout can be dyed a different hue or a darker colour, but it can't be made lighter with dye. The lighter your grout, the more dyeing options you have. White, ivory and natural grouts accept dye the best, while mid- to dark greys, blues and reds can have mixed results. Practice on a sample board before moving on to the actual project to determine how the dye will affect your grout, and make colour decisions only after the sample is completely dry; the colour will lighten as the grout dries.
How to Dye Grout
There are two ways to dye grout. If you are applying grout to a tiled or mosaic surface for the first time, you can add powdered dye directly to the grout mixture as you mix it, then apply it as usual. If you need to dye existing grout, brush a liquid dye onto the grout surface and allow it to dry. Use the grout dyeing technique that suits your needs best; dyeing supplies for either method can be found in the tile section of a home improvement store.
Dye of any type can be toxic, so wear gloves and a face mask when handling dye liquid or powder. If you want to dye the grout on an existing floor, the floor needs to be clean and dry before you begin. No matter what colour or method you choose to dye your grout, the room the grout is in will be unavailable for use for about 24 hours while the dye or grout dries. As with any home improvement item, keep grout dye away from children and pets.