Morning. Had the bathroom tiled, and unfortunately, need to make an alteration. Not 100% sure of best way to proceed!

I’d left a hole in the cement board backing with the shower unit in it. Hole was large enough for casing etc. to slide over. However, the tiles have gone on right to the shower valve, i.e. reducing the size of this hole, so I need to take off c.20mm all around.

Would getting a diamond tile bit of 20mm from screwfix and slowly drilling out the additional diameter be the best way? It’s the only thing I can think of, short of chiselling the tile off and starting again.

Any ideas or tips?

I’d use a small angle grinder with a diamond blade. You can cut quite accurately with them but you could run into problems if you want to make very small cuts due to size of the blade.

Be prepared for dust though!

Have you got a spare tile to practice on?
You can nibble away with a pair of pliers up to scribed (with diamond cutter) line.

DON”T get a grinder anywhere near them! the sparks get very hot and could embed themselves in the lower tiles or the bathroom fittings, I’ve seen it happen.

I’m presuming it’s a concealed shower valve? in which case, yes, I think you’re on the right lines with trying to drill the spare away, get a good tile drill though. I use Black and Decker Pirhana ones, they’re very good. Don’t drill all the way through at 1st, you need lots of holes close together for this to be a success and the tile drills are tapered, so I’d drill in about 5mm, then stop and start another hole near to the last, once you’ve been all the way round you can finish drilling them through. you can them tidy up the edge with a round file, I have a carbarundum one made for tiles but most should work.

Take your time though as it’s not easy, I hope for your sake that the tiles aren’t porcelain! if so you’re in for a long day.

You say that you had the room tiled? speaking as a tiler, is ringing up the guy that did it not an option to ask if he’ll sort it out if it’s a mistake, I know I would if i’d done it. just a thought.

Ta. I’d thought that if I was drilling I’d want to keep it wet, which might help with dust. Angle grinder presumably doesn’t need/want to be wet.

Doesn’t need to be precise – hence I’d thought a series of wider holes – because the fascia covers it comfortably.

richmars – yes I have. Will practice. I’d also thought of scoring and breaking, but wondered whether it might be slower, but also less chance of making a big mess?

Blazin-saddles – yes it is. Would it be worth hiring a drill, I’d thought I might just get a good bit and use my pwer drill with hammer switched off?

It was a miscommunication. He’s on standby to replace the tile next week if need be. I’d like to get it done today though without smashing the tile if poss.

The guy who tiled our bathroom just used a cutter to score a line along the tile and then tapped the required part off with a hammer while resting the tile over a straight piece of wood so the scored mark was over the edge of the piece of wood.

Roter Stern – the tile’s on the wall unfortunately.

Roter Stern – the tile’s on the wall unfortunately.

Ah! Then that method may be a little problematic! 🙂

Phew. That wasn’t too bad. Picked up an 18mm diamond core bit, and went all the way round. Quite a few holes, and a nice pretty edge! Fortunately covered up by the shower bezel.

Thanks for all the suggestions.