Tiling Height Problem - With Image - Please Help!

[Tozzy]

Hi everyone,

This is just a preview of the problem I'd run into if I didn't prepare my surface. Please note, the tiles there have not been laid yet.

The concrete (in purple) is higher than the blue tiles. I thought of boarding down with ply and packing underneath where necessary, then I will have to do the same where the blue tiles are which I can't do because the ply can only be 18mm thick and I don't think I can lay battens underneath because it would sound hollow (presumably?). Other option is to hack away where necessary at the purple concrete, but would be one hell of a job. I've tried it and it is as solid as a rock . Perhaps I could raise the step that those tiles are laid on with cement and sand? Although it would be too thin . I just don't know what to do .

Does anyone have any advice if you were in my shoes?

Maybe use 3 sheets of 18 mm ply on the step and 1 sheet on the concrete and they'll be at the same height then? It' just this rule that's bugging me about having to use 18mm ply.

Thank you.

P.S. Notice how out that spirit level is lol?

 

[Monsoon]

just to clarify,

The concrete is at highest point then there is a drop down to a step then another drop to the area you intend to tile?

What are the differences in mm between the existing surfaces?
What is the surface of the step and the area you intend to tile?

 

[gcol]

I'm not totally sure what you're doing with those blue tiles - are you tiling stairs or something?
That aside, for floor tiling you want 18mm minimum. 18mm will do fine but 25mm would be better - you're not restricted to using 18mm only. If you like you could use a thin sheet of ply over the top of the 18mm to save you buying a large piece of 25mm. Just make sure you glue it and screw it well.
What are you covering the concrete with? And what are you doing with the yellow section inbetween?

 

[Tozzy]

What are the differences in mm between the existing surfaces?

18mm roughly. So maybe I could use 36mm ply on the step where the blue tiles will be and 18mm ply on the concrete (as shown in purple) then they will be at the right level for the tiles. Is this right?

What is the surface of the step and the area you intend to tile?

Dusty concrete, but it's very bumpy and has dips so I want to ply over it.

I'm not totally sure what you're doing with those blue tiles - are you tiling stairs or something?

I intend tiling the stairs and the floor. See here:

(Just a quick rough idea of how it will look later.)

So in other words, when I get the levels corrected, the final level should be like this:

But, at the moment, the stairs are lower than the purple concrete which means I'd either have to chip away some of it (which I really do not want to do) to bring it to right level or ply the stairs and bring them higher to the same level as the purple concrete, but I want to ply over the purple concrete too so I'd have to use double the thickness on the stairs as the concrete is already high to begin with.

So, if I put 18mm ply on the stairs brings both surfaces to the same level without any on the purple concrete, 18mm on the purple concrete which would make the stairs lower again so an additional 18mm on the stairs .

This is the most important question:

Do I have to use battens even on the floor? Can't I just lay the sheet and screw it down without battens? I know you have to use battens if it was a wall, but I'm not sure sure if the case is a floor.

What are you covering the concrete with?

Ply because it's got loads of dips.

And what are you doing with the yellow section inbetween?

Just raising that with a bit of sand and cement to bring to the same level as the stairs.

Thanks for replies both of you.

 

[gcol]

Ah it's all become clear now. Nice pics Tozzy - it's so much easier to understand like that.
OK, I'll go along with screwing down some ply on the step, but on the concrete I'd use self levelling compound. I'd only tile onto ply if there was no solid substrate. Seems a shame to cover up concrete with ply when you just need to level it.

 

[Tozzy]

Ah it's all become clear now. Nice pics Tozzy - it's so much easier to understand like that.

Thanks Gcol . Well, you know what they say: "A picture paints a thousand words"

Yea, you're right about the self levelling compound. I could use that on the concrete. The only reason why I didn't go ahead with it was because I read that if the floor is out by more than 0.75", it wouldn't be possible to use, but I really don't think it will matter too much. I know someone who used it to raise their floor a couple of inches or something lol . A couple of CM should be fine for my floor.

Ok, all makes sense now!

Thanks again . Right then, I'd better go and get my screed laid .