Tiling Preparation

[SR44]

I am about to tile over an existing tiled bathroom floor. The existing floor is in good condition, it is just dated.
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I plan on giving the existing tiled floor a good clean with sugar soap, but apart from this can anyone suggest a suitable preparation for the existing tiled floor – e.g scoring the surface (with what and how) or perhaps a solution to etch the tile?
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Thank you

[silentC]

You're far better to dig up the old tiles first. Hire a kango hammer and have at it.

[Honorary Bloke]

G'day SR44. Welcome to the Forum.

If you tile over existing tile alone, you will live to regret it. For one, it is unlikely that your current tile is absolutely flat on the top, and new tiles want dead flat to avoid cracks from walking, etc. Plus, you will be raising the level of the floor and changing the transition from one room to another. I agree with SilentC, far better to chip them up and start afresh.

[mic-d]

I'm going to disagree with you both. If the old tiles are sound, there is little reason to dig them up. It is a messy, messy slow job and you have to make sure that every little dag is removed so there is nothing to foul the new tiles. Sometimes the tiles may come up easily, but more often not. Only if there is unsoundness or a clearance issue that just cannot be solved would I take up the tiles - and this is standard practice, it's not bodgy as some people think. The tiles can be edged with some very pretty transition edges to accommodate floor height changes and if the tiles are not true as tested by a straight edge, you can top them in the low spots very easily with a bit of cement -based tile adhesive which you allow to dry before setting the tiles. I would suggest roughing the surface of the tiles with a diamond blade first. Use a cement -based flexible tile adhesive, I use Mapei, but it is expensive.

Cheers
Michael

[silentC]

Yeah fair enough I suppose. I still wouldn't do it myself but if it's too much trouble to dig them up, then go for it...

Regarding messy and slow, I've done it a couple of times now. It doesn't take that long with a kango and a scutching bit. We had to do a couple of bathrooms in a private hospital once and the old tiles were dug up, then a new screed and new tiles over the old floor (concrete slab). It was a mongrel in places but there was no way they were going to cop laying the new tiles over the old. It didn't matter if the floor was a bit rough with dags left here and there because the new screed took care of that.

[celeste]

Hi all

I have tiles over tiles - DAVCO have a 2 part product you can put down 1st, it will add about 2-3mm and you can fix any low spots at the same time, it costs approx $70.00 and you can get it at any tile shop that carries DAVCO.

Celeste