Bathroom floor

[red7jase]

I know this question has been asked a million time but i confirm the procedure - I am laying ceramic tiles in the bathroom

Is it best remove floorboards and replace with 18MM wbp
or put a thinner WBP over the existing floorboards, I dont really want to raise the floor much problems with join and door ect.
Also as the bath runs down the side of the room covering just under half the room and i am only floor tiling the other half do i only need to place the ply on that half of the room for the tiles, as i dont belive i need to tile under the bath.
I then place the bath directly onto the floor boards.
If i remove the boards and replace with ply do i do whole room or just the half that is to be tiled.
thanks

 

[Softus]

I know it's always a dilemma, but I'd make your decision based on the soundness of the existing floorboards. If they're good, and perhaps just a little bit loose in places, then I would screw down everything that isn't already firm, then screw a layer of WBP on top. If you can afford the height then use at least 9mm so that it doesn't flex toooo much.

If you decide to replace an area with 18mm WBP, then how much you replace depends on how matching a level you can attain.