I have taken out the flooring (knackered) in my bathroom as I would like to lay ceramic floor tiles down. I am about to lay marine ply down. I have had conflicting recommendations on the size to use. Some say 18mm (to keep height down) others 25mm (belt and braces). Any advice would be much appreciated. Its a trad semi bathroom ca. 2.5m x 2.5m and joists are in good nick. Thanks in advance.
