Floor tiling: discard old floorboards and replace with ply?

[Meeeeshell]

Have read previous posts with interest but would appreciate clarification on the following:

I intend to lay ceramic floor tiles in my bathroom. The floorboards are of the traditional kind (ie not chipboard sheets). If I was to cover the floorboards with 6mm ply, along with the depth of the tiles and adhesive it would create a step up from carpet in the hallway of about 25mm, which is not acceptable. The bathroom fitter (who is not doing the tiling, incidentally...) suggested that I should take up the traditional floorboards and replace them with 18mm floorgrade ply. I intend to do this unless anyone advises against it! Is there any reason why this would not work? I intend to insert noggins between the joists and will screw the ply down at small, regular intervals to reduce any risk of movement. I will be using BAL powdered flexi adhesive and grout for this job. Is there anything else I need to do?

I'd really appreciate your help!

Thanks!

 

[ChippyBoy]

If your boards are tongue and grooved than you can use bal fastflex. If not then the plywood option in 18mm is the way to go, but a coat of unibond to the plywood would be a good idea.

 

[Jasonb]

I tend to use 22mm T&G plywood if I'm replacing a floor but as you are using ceramic as against natural stone you should be OK, provided your joists are at 400mm cts or less.

DO NOT unibond the ply, your spec for adhesive is fine just spread it onto the ply, I would go for rapidset flexible as the room won't be out of action for 24hrs.

Jason

 

[Meeeeshell]

Thanks guys!

That's really helpful!

This is an excellent forum, btw! Fascinating stuff.

 

[joe-90]

If your ply is 18mm that is the same thickness as the floorboards you are taking up, so when you add adhesive and the tiles you will STILL have a step.

joe

 

[Jasonb]

If your ply is 18mm that is the same thickness as the floorboards you are taking up, so when you add adhesive and the tiles you will STILL have a step.

joe

Which will be cancelled out by the thickness of any carpet,underlay in the hallway

Jason

 

[Meeeeshell]

Old floor is at the tip; new 18mm marine ply is down. Looks like it'll work a treat. I've put a tile down and hardly any step up - as Jason B says, it's cancelled out by the carpet and underlay.

Thanks again, you've been a great help! It's so much better when you have confidence your plans will work!