Tiling on wood floor - please bear with me!

[Mark Begbie]

Right I know this has been "done to death", and I have had a rake through the archives, FAQs, etc. but ........

What I want to do is tile a sprung wooden bathroom floor so that the top of the tiles is, so far as possible, at the same level as the old floor. This is because the hall will be stripped boards and the bathroom is off the hall. Now, I have read all sorts of things about this and there seem to be two categories:

1) Ply on top of boards - fails on the height criterion 2) Super flexible adhesive - just not keen and want a stiff floor

So, is the following sensible given 1950's 6"x2" joists and a maximum span between the brick walls of 2m?

Option 1:

Remove boards Screw 2"x1" battens to the joists 18mm below the joist tops Angle screw 18mm chipboard to battens and joists, flush with joist tops Screw down 18mm WBP ply to the joists (long screws) and chip (shorter)

Option 2:

As option 1 but don't screw down chip. Instead leave loose, but coat with PVA and screw down ply to make 36mm stiff composite which is then screwed to the joists. (Aim here is to make lifting a bit easier whilst retaining stiffness)

Bad ASCII drawing below

==========T========== Ply ======\=| | |=/====== Chip |\| |/| Batten -| |- | | Joist ---

[Grunff]

[Grunff]

So that's 2 layers of chip, right? One flush with the joists, and another on top?

Whatever you do, you will still need to use flexible adhesive. The reason is your wood will still expand and contract to some extent, regardless of how stiff you make it.

Given this, I'd be inclined to just remove the boards and replace with

18mm WBP. PVA, then tile. A lot less work.

[Clive Summerfield]

So that is chip between the joists, with 18mm ply on top. Seems a bit of overkill.

If you're worried about flexing, I'd take the following approach.

Lift the existing floorboards. Insert 6"x4" noggins between the joits, offset to allow you to screw through the joists into the ends of the noggins. Lay 18mm ply on top, screwed to joists and noggins. Use flexible tile adhesive

Cheers Clive

[The Natural Philosopher]

If the floor is flexy, I'd double up on the joists at the same time. Or exapand your battens to fill teh salce to teh celing below.

Otherwise I think it all looks a sound way to go?

Do still use flexible cement and fairly thick.

[Mark Begbie]

Thank you guys. To clarify, the original suggestion was chip between joists, ply on top. But it seems like that woudl be more than I need to do. So I guess, noggings it is, then screw 18mm WBP down on top, good coat of PVA then tile. A couple of follow ons:

How frequent would you make the noggings? Do I have to coat the underside of the WBP with anything (for regs)?

Mark

[Pete C]

Hi,

If you want to make the floor stiffer, one way is to put something on top of the floor which is strong in compression, like wedi board

This is also waterproof and can be tiled onto directly.

cheers, Pete.