Do i need to level floor before tiling ?

[bob the builder 2]

Hi All

 

We have a raft foundation concrete slab which is a bit ruff and uneven due to rain during the pour (about 5mm out in places)

 

The idea was to tile straight onto the concrete but the tiler has now said they want to put latex down to level before tiling partly because the tiles are large format.

 

Obviously this was not in the budget !

 

Any views on this being required or alternatives to latex would be gratefully received

 

Bob

[nod]

No you don’t need to level out 

Large format tile require a thick bed 

5 milis nothing 

[bob the builder 2]

Hi Nod

 

That's what i was lead to believe - the tile has about 10-12mil bed and this would be more than enough to even things out.

 

I wonder if this is the tilers just trying to sell another service and also make life easier for themselves ?

 

Bob

 

[nod]

If they are large format 12 mil will be minimum 

Putting latex down is a waste of time and money 

[Russell griffiths]

Who’s paying for the adhesive, large format and an uneven surface will result in lots of adhesive. 

Allow for loads extra. 

[saveasteading]

13 hours ago, bob the builder 2 said:

wonder if this is the tilers just trying to sell another service and also make life easier for themselves ?

A standard try-on from flooring contractors, along with damp-proofing concrete. Easy money extra job for them, at your expense. 

Thin latex doesn't stick as well as tile adhesive anyway. 

I think the discounts on adhesive are good for tilers, so just £10 extra.

 

This is all assuming that it is generally level, but uneven. Have you put a long straightedge on it?

 

[bob the builder 2]

Hi

 

The surface i rough and about 5mm out in some places (dips around doors etc) where the concrete went down uneven.

 

I really don't want to  / cant afford to have 160m2 of work done if i can get away without it.

 

If there something i can do myself like a bit of self leveling if required ?

 

thanks 

[saveasteading]

6 minutes ago, bob the builder 2 said:

If there something i can do myself like a bit of self levelling if required ?

Yes you can sort those 5mm dips out beforehand with self leveller. It will be very thin so make sure to get a product designed to be thin (it is on the bag).

I might be tempted to use tile adhesive instead.   It is nice to work with, goes on thin and sticks like...

The general roughness shouldn't matter, assuming it is 1 or 2mm blips. want to send a pic?

 

The advantage of doing it in advance is that the tiler wont be perching tiles on very thick adhesive, with possibly some voids.  Shouldn't happen as I learnt the wonders of double buttering.

Maybe someone on bh is an actual tiler and can confirm or contradict.

[Bozza]

I had a similar problem with my barn/large shed floor. Really rough at parts 20mm out at bits.  As it was a DIY mix and pour something I’d never done before.   No nonsense leveller from Screwfix worked really well for me and it came out really smooth and level.  Not latex based though.

[MikeSharp01]

23 hours ago, nod said:

If they are large format 12 mil will be minimum 

Wonder what the definition of large format is. 600x600 bigger or smaller?

[bob the builder 2]

Hi All

 

 

here is a sanp

 

the concrete is quite ruff but only 5mm out in a few places (its a new raft floor)

 

the tiles are 1.2 x 1.2m so large 

 

Do you think i can just get away with the adhesive or should i be levelling as the tiler suggests

 

thanks

[saveasteading]

31 minutes ago, bob the builder 2 said:

should i be levelling as the tiler suggests

 

Most people are surprised how much variation there is in what looks like a smooth slab..eg a b & q shed. There is a difference between smooth, and level.

 

also that i have known a flooring company want a smooth concrete floor to be scabbled to get a grippy surface, and it then looked like yours.

 

I can't really say any more because it has to be up to you and your relationship with the tiler.

 

If you wanted to persuade him that it was ok, you put a long spirit level down and see how much gap there is. 

[Temp]

I've just laid 60cm * 40cm stone in a bathroom. Floor was perfect but the stone varied quite a bit in thickness. Was using a big notch trowel but found it very difficult to judge how much adhesive to back butter the stone with. Kept using too much on the thinner tiles and finding I couldn't press then down far enough. Hard work lifting, cleaning and starting over. If they had been uniform thickness I could have done the floor in a day but it took me about three days. The varying thickness made the tile levelling system much less effective as well. I'm only a DIY tiler but Im fussy when it comes to tiling and it's got to look perfect. Perhaps it wouldn't have been such a problem for a professional.

 

Edit: Oh and I used double the adhesive I calculated.

Edited January 8, 2023 by Temp

[Nickfromwales]

10 hours ago, bob the builder 2 said:

Hi All

 

 

here is a sanp

 

the concrete is quite ruff but only 5mm out in a few places (its a new raft floor)

 

the tiles are 1.2 x 1.2m so large 

 

Do you think i can just get away with the adhesive or should i be levelling as the tiler suggests

 

thanks

I've tiled floors where the average undulation was ~10mm, and that is doable tbh, but that was with 600x600mm tiles. 1200x1200 will be a pita to lay, lift, re-lay etc so I can see the tilers concern.

Unless one of us is going to come and tile it, this is moot tbh. As your tiler is stating what standards they are willing to work to, and how it should be done, if you deviate from that they'll probably tell you to do it yourself ( which is what I would do for sure ).....

Levelling out few patches here and there, if it's as minimal as you describe (?), should be a half days work for the tiler. Just pay the tiler to do the spot-prep and get out of their way??

 

I use Ultra 2-part SLC and that's never once let me down. Will feather out from 5mm-2 to 3mm so don't go to the absolute edges of the ares you wish to level. Tile adhesive is more than capable of absorbing 3-5mm tbh, ( so this is a little bit like splitting hairs in absolute honesty ). 

 

Pay the tiler to prep the areas of doubt ONLY, and crack on with the tiling. If you or other get involved and the floor gives up, then expect the tiler to tell you it's your problem not theirs.