DerbyBorn wrote:
Our current floor is tongue and groove but with significant gaps and the
boards are slightly convex.

SWMBO would like something better than the existing carpet tiles but I
realise I need to overboard it in some way. I guess I need something like
10mm ply but I really am concerned about making a step as my wife is always
tripping.
Could I get the floor sanded flatter and get away with something thinner to
overbard it before tiling? Could I use a floor leveling compound?

Not sure if I want ceramic - possibly a lino plank type of covering.

Compressed cement sheeting,either on or instead of existing flooring..

http://www.jameshardie.com.au/produc...pressed-sheet/

Can put pretty much what you want on it but ceramic tiles best..