Porcelain tile on concrete - How flat does it need to be?

[sharrow]

Hi

Maybe a naive question but...

Am going to lay 450mm square tiles onto a sound exisiting concrete floor and I'd just like an idea as to how flat the floor should be before I start? It's generally pretty good with around 5mm variations in height with one edge being maybe 10mm high.

Do I need to level this before I start?

Thanks

 

[gcol]

Yes you do. 450mm tiles will show up any irregularities. The flatter you get it before hand the easier it will be to lay and the better the result will be.

 

[Moz]

Do I need to level this before I start?
yes ...