18mm chip board an tiling answers

[Moz]

I see mods locked a thread below ,

but if you wish to tile on wooden substrate/floors ,
it needs to be 18mm ply on joists
in wet areas wbp or marine 18mm ply ,

the joists may need strengthening with wooden 2/2 battens, called noggins ,
I always thoroughly soak the joists an noggins in wood preservative
then the ply needs to be screwed down with stainless steel wood 50mm screws at 200mm centres , (every other 200mm put a screw into the ply an joist ,)
hope this helps