How to replace missing tile grout in walls?

hardwarefan

Some of the grout is coming off in the kitchen and bathroom. I just want to touch it up so there isn't an obvious gap as its only in a couple of areas. What can I use? (note in the bathroom walls there will be steam from showers).

Also do I need to use a water based white silicon if replacing moldy bits, as I can't clean the mold off in the bathroom vanity or kitchen sink?

Thought you guys would know, thanks!

JacobZ

Hi @hardwarefan,

While there is only a small piece of grout that has fallen out, you can see the cracking extends out past that missing section, which means the whole grout line is compromised. This is an indicator that there is movement around that grout line. Ultimately, if there is significant movement in the tiles, then any grout applied to that line is likely to crack in the long term.

If you gently press on the tiles either side of the gap, can you see them moving? If so, is the movement minimal or is there a significant rocking action?

If there is minimal movement, then I'd say it is fine to just replace the damaged grout along that line, but if there is significant movement, you may have to look at ways to reduce it, such as removing and replacing the tile with additional tile adhesive to ensure it is more solidly attached.

Assuming movement is minimal, then you would start by removing the cracked grout. This can be done manually with a https://www.bunnings.com.au/qep-professional-grout-saw_p0393523 by scraping up and down the grout line. As it is already cracked, it shouldn't be too difficult to remove it. Make sure you get every bit of loose material out of the crack. A vacuum is handy for this.

Once the cracked grout has been cleared, use a premixed white grout such as https://www.bunnings.com.au/dunlop-800g-white-ready-to-go-coloured-grout_p6650123 and ensure you fill it to the full depth of the tile.

You can then smooth the grout and tidy up with a damp sponge.

Check out https://www.bunnings.com.au/diy-advice/diy-skills/tiling/how-to-grout-wall-tiles for a bit of extra guidance.

Let me know what you think and if you have further questions, please don't hesitate to ask.

Jacob