(inNeedofHelp) wrote in message . com...
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

not in MHE. 18mm will bend, bounce and bow on 400mm (BTW whatever
size make sure it is floor grade & moisture resist - moisture slowly
over the years swells chipboard until it is like cardboard). I ripped
up mine & replaced it with 22mm T&G in the bedroom. I used 22mm in
the bathroom well protected by varnish & vinyl floor tiles, that has
been OK.




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?

18mm is a waste of time & money

It is a tenament 1st floor flat in case that makes a difference.

What are the best materials for packing, I was just going to use some
hardboard I have.

If yoo're putting heavy weights on the floor, especially dynamic ones
like a washing m/c, you should look at reinforcing the joists, perhaps
by doubling up and/or by (additional) herring bone strutting

You can make a guesstimate as to what is needed by jumping up & down
plus observing what happens as you walk slowly over the floor -
perhaps 2 people together if you're small.

I've no experience of plywood, but I have been told by those who have
that 18mm or thicker ply is superior to both chipboard & T&G for
rigidity.

HTH