BigWallop wrote:


Can you replace the floorboards with ply? Ply glued and screwed to the
joists is a *lot* stiffer than boards so you buy more stiffness for your
thickness. As you are tiling the floor, there's not much to be lost by
gluing the ply too. But if that worries you, use screws every 10cm or so
into every joist (not just round the edges of the ply).


Now then. That's an idea. Remove the old boards, which are quiet nail
sick, and lay new chipboard flooring. These old boards are nearly an inch
thick, so chipboard flooring matches better in thickness.

While I'm under that part of the floor, it;s easy to bash in a line of
noggins to make the joist don't wobble. Thank you for that suggestion,
Tim.


Ok - there's a plan then.

As I don't to be responsible when you come back in 3 months saying the tiles
are cracking, here is what *I* would do:

While you have some of the floor up, go and buy some ply insmall section
size (Wickes or B&Q sell cuts - you want the 2x4 foot size as it's small and
cheap enough.

Remove enough boards to put that direct to joists, and screw every 10cm or
so. Now you can do some deflection tests. Your worst enemy will be the
washing machine on spin - the weight and dynamic loadings will be very high.

If your floorboards were 25mm thick, you could even consider going up a
thickness in ply if it seems necessary. Depends a lot on your joist spacings
but tiled floors are commonly done by tiling to ply over joists and I have
seen at least one and that was fine.

Don't forget to have a plan about underfloor services - like not having them
under the tiled area or you will regret it :-o

Cheers,

Tim

--
Tim Watts