I have some white tiles with white grout which has gone miscoloured / dirty etc ideally want to regrout a darker colour - how easy is it to do this - looks like a ballache !
It is a ballache. You need to gouge out the old grout (only halfway down though) and then re-grout. I did it to my bathroom a few years back, had to buy a hand tool for digging the old grout out (sort of blade thing). Couldn't find a power tool to do the job - probably not a great idea anyway as you might accidentally ruin some tiles. Best of luck.
Or you could try a grout pen to refresh them. If you are strapped for cash and the tiles aren't limestone you can get the bleach and old toothbrush out and give that a go (wear goggles).
If you’ve a friend with a dremel they do a reasonably priced tool/accessory to remove the grout. It’s fundamentally f’in hard work removing grout even with the dremel, not a lot of option though. Don’t think I’d be adding food colouring to white grout though, sounds like a disaster waiting to happen.
All the above methods will work, but to make it slightly easier you can try to soften the grout with lemon juice, or proprietary grout softeners are available.
I decided to spruce up my bathroom, it had been tiled about 25yrs ago,the tiles were in good nick but the grouting had gone a dirty grey.. I tried several methods and products that are supposed to restore the colour... they don't work. I went on a tilers group on the net and one guy said the only way without grinding the old stuff out is to paint the grout... I followed his advice and its like a new bathroom... loads of 'Frogtape'... mask each line from top to bottom and paint it twice with a good quality white emulsion, then repeat for the horizontal grouting... very time consuming but it looks great, I'm not sure if it would work changing the colour though. The only thing I would add is that the original tiler did a great job, they were put on very neatly with all nice straight lines.. if the job had been a bit rough and ready I don't think it would have looked very good. I'll try and post a pic later. here you go. <a href='https://postimg.cc/S2vCkGKX'
If you intend to do it yourself these are the most likely scenarios: 1 You never get round to buying the equipment and it never gets done, but at least it doesn't cost you anything. 2 You buy the stuff you need but never get round to actually doing it, so you're out of pocket for no benefit and periodically the other half gives you grief for not doing it. 3 You buy the equipment, you have a go, it takes you all bloody weekend to get the old grout out leaving you no time to start with the new, you've broken three tiles, the mess is unbelievable and you're up until the early hours cleaning and you now have a bathroom that isn't water sealed. You start after work the following week but it's much more difficult and you are much less talented than you imagined and after five hours of toiling you've managed to grout one tile that you're really not very pleased with, meanwhile the grout is everywhere, it's in the bath and the sink and all over the carpet and the dog and no one can have a shower and you're hundred quid down and you want to die. Get a professional in.
Number 3 is as if you watched me repoint my old house. Or at least a 3ft by 3ft square of it before I gave up.
That’s what I thought - like a dye of some sort, but it seems not. If you can crack this, get yourself on dragons den and there is no such product out there
You can paint it. The reason you can't dye it is that the whole point of grout is it prevents liquids from absorbing into your walls. It's impervious to liquid. That's why it's there. If you didn't have the tiles and grout your walls would become waterlogged. So you can't dye it as that would require grout that absorbs the fluid, which entirety defeats the point. You can colour it by applying a substance that will adhere to it but sit on top of it. We call that paint. A water proof masonry paint would potentially do it. But it would look a right cnt.
Mix bicarbonate of soda with bleach, into a paste, apply with a toothbrush onto your grout and it’ll come up like brand new. Then, every now and then, spray mildew remover on it (Screwfix’s No Nonsense stuff is about a fiver) which will prevent it from discolouring again. Or, as others have said, raking the old grout out, to re-grout, is a serious ball-ache.
Have you tried using Tip-Ex? I'm pretty sure that would return it to its original white colour at minimal cost.