Bathroom floor renno questions

[Arron]

Hi Folks. The bathroom renno is progressing. Now I'm looking at the floor in the toilet. This is a 1963 house in Sydney, with original bathroom and toilet.

The floor is on a floating slab, with those tiny tiles. When I started on it I expected there to be a layer of sand and cement about 30mm thick beneath the tiles, sitting on top of the concrete. Ie concrete floor under mortar bed under tiles. It seems that is not so and it seems to be solid concrete directly under the tiles. I've bashed a hole in the floor and it just looks like concrete. The problem is that the old tiles are only about 4mm thick, so replacing these with bigger (modern) tiles and a layer of adhesive will raise the floor - making it too high in relation to the adjoining wooden hallway floor. Also, the floor is slightly dish-shaped, which is OK with the very small tiles but isnt going to work very well with 200x200mm tiles, and will need a thick adhesive bed to compensate.

Is my conclusion on how the floor is made likely to be correct - or am I just not seeing things right. If so, how is this type of floor normally retiled. Any suggestions on how to get a nice flat layer of tiles in without raising the floor and creating a little step, always to be tripped over.

I've included a photo showing floor with some the tiles removed.

thanks
Arron

[mic-d]

If you bashed a hole in the floor and found it to be concrete then it probably is conctrete :D . Typically I would leave the tiles in place if sound and tile over top. Use a self level compound to correct the floor, not the tile adhesive bed. Even 40mm steps are seldom tripped over IMO, but you can also fit a transition edge if you're worried about that.

Cheers
Michael

[ian]

It's possible, though unlikley, that the original tiles were glued straight onto the concrete slab. A friend aimed for this approach on his own house about 10 years ago, put a lot of effort into getting the kitchen floor perfectly level, then the tiler turned up and placed a motar bed anyway!

If you don't mind the effort, you could score the floor 30-35mm deep every inch or so using a diamond saw then knock off the ridges with a chisel hammer this will lower the existing surface enough so that after placing and leveling a new motar bed the new tiles will be at the "right" level. But as I said it's a lot of work.
In terms of tools, Makita make a 125mm dustless cutter that uses 125mm diamond blades. Alternatively you could use an angle grinder and diamond blade but going this way it's much harder to get a consistent depth of cut depth.

[journeyman Mick]

"Dustless cutter" has to be the worst case of misleading advertising ever (or a misnomer at any rate). I've used one for hours on end (major rehash by clients on 48 bathrooms) and buggerall dust ends up in the bag. :mad:

Mick

[Arron]

Thanks guys. It looks like the tiles are sitting on a concrete floor with just enough mortar to stick them down. I'll have to go with a small step - everything else looks like too much work.

Anyway, it is a renno job and I cant expect things to be perfect.

Arron

[ian]

Mick
your experience is certainly a lot different to mine. with mine most of the dust ends up in the bag and compared to the alternative of using an angle grinder it is "dustless". If I attach it to the festo dust extractor it is truely dustless.

Ian