Self level or Ply

[charlieh]

Hi, I have a concrete floor 3m x 3.3m which I need to raise by 12mm so that I can lay 300mm x 300mm ceramic tiles. Its an old floor which looks sound,my question is, do I use self leveling compound (if so which is the best to buy and can I lay 12mm in one go) or can I lay 12mm exterior ply straight on top using gripfill, if so would I have to screw as well, and what would be the best way to screw into the slab?
any help will be much appreciated.

 

[Jasonb]

You could lay Aquapanel or similar in a bed of tile adhesive this would give about 15mm gain (12 + 3) and be a lot better than ply.

Most leveling compounds will need to be done in layers but they can be bulked up with granite dust to allow thicker layers.

Jason