Grouting is a mixture of cement, sand and sometimes epoxy; it is used to fill the gaps between tiles and (partly to) hold them in place. It is designed to be waterproof, provided that it is made from a fresh compound and applied well. Grout can be coloured to suit the style of tile.
Why coloured grout?
Tiling should look good as well as function well. A grout colour that matches the tiles will make the tiles floor look continuous. It will also cover smaller imperfections. A grout colour that contrasts with the tiling will make the individuals tiles stand out. Dark colour grouting and tiles tend show the dirt less than lighter colours. Both are reasonably easy to clean.
Can grout be lightened or darkened?
Older grout can become discoloured over time. Cleaning with vinegar and bicarbonate of soda can restore the original colour, but cannot lighten the grout any more than this. Grout can also be stained a darker colour. This is so effective that it makes the tiles look new.
What is sanded grout?
This is a stronger form of grout, the extra strength being required for any gaps more than 3mm in width. This is more common with larger tiles, such as in modern kitchens.
What is sealing
To be properly watertight the grout should be sealed. This is a compound applied to the grout after installation, and reapplied annually. Properly sealed tiles last for many years.
Does grout hold the tiles in place?
The tiles are initially adhered to the floor with mortar. Once the mortar is set the grout is applied between the tiles. The grout holds the final job together. The mortar under the tiles is only part of the job. Apart from filling the gaps between tiles the grout is necessary for locking it all into place.
Why is regrouting difficult.
Grout is designed to be strong, and hence hard to remove. It is also positioned between in small spaces between tiles, so removal is delicate work if you do not want tiles damaged.
Most people choose professionals to assess the situation with their tiles and undertake regrouting. The results are long lasting.