"inNeedofHelp" wrote in message
om...
Hi,
We are planning replacing our floorboarded kitchen floor with
chipboard. The boards are in bad nick with being cut over the years
and lifted for electrics and heating. The joists are spaced at 40cm,
from middle to middle
so according to readers digest 18mm Chippy would be fine.

http://www.readersdigest.co.uk/diy/webpages/274_275.htm

I am wondering if 22mm would be better as I will have less packing out
to do, to bring the floor to the same level as the hall as the current
floorboards are around 25mm thick. Or should I stick to 18mm and use
something to pack it up to the height of hall?
.....
Then I can put a layer of ply down and tile. Actually this will add
height, so should I worry too much about making the chipboard floor
match the hall floor height? ...

If you use chipboard, there ought to be no need for the layer of ply and the
tiles ought to add just enough height for 22mm to be the right choice.
However, make sure you buy the water resistant grade, which has a green
colour.

Colin Bignell