The tile grout in our bathroom is a lovely whitish grey colour, which is nice, apart from the fact that it’s meant to be black. When the grout is wet, it goes jet black, but when dry it goes back to the greyish colour. Are there any products out there to darken/seal/fix the problem? The floor is porcelain so guessing whatever I use on the grout may stain the tiles a little. I can live with that.

As a bodge, I have some slate oil kicking around, which I know will solve the problem, but will also turn the floor into a skating rink so not exactly the right solution.

Thoughts?

Mapei make a fruga fresca grout rejuvenator product which refreshes the colour without damaging the tile. Not used it myself.

Thats possibky the efflorescense.
Google may be your firnd to how to deal with, also sealing it with a penetrating sealer nay help, but do thisbafter touve addressed the installation issues.

the grout was fine for quite some time, so I don’t think this was an installation issue, but I agree that efflorescence is the likely reason. Done a bit of googling and getting differing results. So far, I’m thinking on attacking the grout with some brick acid, then taking a penetrating sealer to it – which one, I don’t know…

augmented reality

Sounds like a lot of faff. Probably just easier to remove the grout and re-grout. Not a huge job. You can hire a grout saw for about £12 for a day, it’ll have the old grout out in no time – goes through like a hot knife through butter.

I find I have to re-grout every 5 years or so anyway.

(Wow … sometime i think STW has it’s know Cambridge Analytica working away in the background)

I’ve started to tackle the limescale build up on the grout in my shower. Have hit it with vinegar and it’s come up pretty well but not perfect. I was thinking about regrouting and had never heard of a grout saw before so thanks for that. But as I’m happy with the grout, in general, will i be able to just to take off the top surface (and so the limescale) with a saw ?

ta

Could you not just use a sharpie pen to blacken up the grout?