Laying self leveller on concrete floor

djt0607

Hi,

I've finished tiling a bathroom. It's only a small bathroom (~3 square meters). When putting on the tiling adhesive, I forgot to put a sheet over the concrete floor below so blobs of adhesive dropped on the floor. Now that tiling the wall has finished, I'm now moving onto tiling the floor. My plan is to remove the majority of the lumps of tile adhesive on the floor to get it relatively flat (naturally there will be some tile adhesive residue still on the concrete) and then put some leveler (as the concrete has some bits gone, etc. ) and then I plan to tile over the leveller. I'd say the floor is about 80% free of the adhesive marks.

So to do this, I'm wondering:

1. Do I need to remove ALL the tile adhesive from the concrete subfloor ( even the slightest bit of residue) before pouring the leveller or is what I am planning to do ok?

2. Do I need to treat/prime the leveller/concrete subfloor before I tile?

This is the first time tiling a floor, so would appreciate any advice yee have. Thanks.

mickdw

Relatively fresh tile adhesive should come off with a scraper so get the floor as clean as possible.

Anything lower than your proposed floor levelling build up will be ok but you really only want to be putting a thin skin of leveller on.

If you are dealing with a heavily sloping floor or something like that, there is high build leveller available too.

I'd question whether you need leveller at all though. If you get floor relatively clean, you should be good to tile.

Furze99

Levelling compound is typically cement based, but check what you're using. If the tile adhesive is stuck firmly to the concrete, then the levelling compound will adhere to the tile adhesive. My thinking is that 1) you'd want to get rid of any loose/ flaky material before pouring and 2) any lumps that project above your proposed finish level.

djt0607

Thanks for the replies. In response to your post mickdw, the floor is pretty level. I put the spirit level on it and at all points (and in every direction) the spirit level shows the floor is almost perfectly level.

In response to furze99, most (if not all) of what I can see (of tile adhesive) is gone. It's just the flat residues that are left stuck to the grounds. By residues, I mean when I remove a blob, it leaves a ring or some flat adhesive on the floor that's difficult to remove.

Thanks again for helping me out folks.

asdfg87

Leveling compound and tile adhesive are basically the same thing one part plaster sand one part cement. just make up a small amount and compare.

Just to add i don't think its necessary to remove the adhesive at all but i may be wrong.

mickdw

Surely it's within tolerance now so for the floor adhesive to take up the minor imperfections. Tap of a hammer for any suspect lumps. Indents are not going to cause you a problem.