tiling on plywood

[mondieu]

Hi all,

I am refurbishing my bathroom which is on the first floor.
The old floor consisted of chipboard glued and nailed on wooden joists.
We have replaced the chipboard floor with WBP plywood 18mm and my questions are:
- Is a 18mm plywood floor sufficient thickness as we want to tile the bathroom floor ( area is 2 meters square)?
- Can we lay marble tiles and if yes how?
- Do I need to use a tile backer such as Thermal Aquapanel?

Regards,

David

 

[Time's Ran Out]

Ello Mondieu and:welcome:
Have you screwed the plywood down to the joists and is it all in one piece.
If you have any joins in the sheeting you should overboard or overlay another layer of 'something' - either hardie backer, aquapanel or roll out the ditta matting.
Yes you can lay marble but unless you have tiling experience wet cutting + tools then I would suggest you employ an experienced tiler.Good luck and have fun.
John.

 

[faithhealer]

Welcome friend, good luck with the floor

 

[mondieu]

Hi,
The Plywood is screwed to the joists but not all in one piece and they are joins.
So I should lay a hardie backer or aquapanel on the top of plywood with some adhesive between plywood and boards?
If I use Aquapanel, can I use Aquathermal as it is thinner? (do not really want a step into bathroom)
Is it more simple to lay ceramic tiles than marble? ( I have a wet tile cutter)
It is my second bathroom I try to refurbish but it does not get easier!
Thanks,

 

[Time's Ran Out]

Hi, another day another £.

Hardie backer is 6mm thick and can be screwed and fixed with flexible fast set adhesive - which can also be used to fix the tiles.
Adhesive-board-adhesive-tile, all total approx 20mm high about the same as carpet and underlay at door.However its better to have a stable bathroom floor than find the tiles/marble cracking.
You have to take extra care when laying marble with respect to working on the surface as you fix them, Knee pads and tile chippings etc can cause scratching. The fixing is the same but choose your adhesive carefully and use a white flexible type if it is a light coloured marble. Don't use coloured grouts!Have fun.
John.

 

[mondieu]

Could you please advise me on what adhesive to use ?
Do I need to PVA plywood and board?
Thanks again,

 

[White Room]

No pva, I tend to use sbr or bal apd, use a single part flexible

 

[mondieu]

Hi guys,

Was thinking my 18mm plywood floor may not be sufficient or strong enough as where
the joists join with metal bracket we had to cut in thickness into wood so maybe better to use 12mm backer boards rather than 06mm?
Is Hardie Backer or Aquapanel better to use on plywood floor (area is around 2.5 m2) ?
Would a backer board of 12mm add strenght and rigidity to floor?
Can I use Mapei flex adhesive between ply / boards and boards / tiles as it is cheap and already mixed ?
Apologies to bombard you with all those questions but better be sure than sorry!

 

[grumpygrouter]

12mm hardiebacker is designed for walls not floors. The 6mm hardie is a "denser" product. I am not conviced yet that cement based boards add any strength to a floor though others on here will disagree with me. if you have your floor up anyway, why don't you strengthen the joists first if you have access to them? As it is you floor is only 2.5m2 and as such is not a huge area and I would have thought deflection would not be a big issue.

NO!! Ready mixed adhesive is not suitable for floors, you must use a cement based adhesive, of which Mapei make excellent ones.

 

[mondieu]

The bath is in place so is the basin cabinet so taking ply floor up again is no more an option.
As anyone had the similar issue or have used other methods ?
Shall I then just fix 06mm hardiebacker ?
The tiling floor surface taking out bath is 170cms x120cms and Toppstiles sell hardiebacker boards 6mm 120x80 so just over 02 across would cover most of the
tiling surface required without cutting.
Could I get some other opinions from other experts such as Grumpygrouter , please!

 

[grumpygrouter]

Have you tried to assertain how much deflection you actually have in the floor? One easy way is to fill a glass with water right to the brim and then walk around and jump about a bit! if the water stays in the glass, you don't really have much of a problem with deflection. As a belt and braces if that is the case, I would lay the 6mm hardie and tile away.

 

[mondieu]

I have done the test with the glass of water and no water came out so I suppose 06mm hardie backer boards would be sufficient.
What thickness adhesive should I use?
I was recommended to use Bal SBR OR APD and single part flex as adhesive by an expert on this site, do you mix the SBR/APD to adhesive or apply to backer board ? Is it necessary ?

 

[grumpygrouter]

I have done the test with the glass of water and no water came out so I suppose 06mm hardie backer boards would be sufficient.
What thickness adhesive should I use?
I was recommended to use Bal SBR OR APD and single part flex as adhesive by an expert on this site, do you mix the SBR/APD to adhesive or apply to backer board ? Is it necessary ?

The SBR is usually to seal the back and edges of the ply before fixing it to the joists. If you are using BAL adhesives, it is not necessary to prime the floor before tiling, neither with Mapei adhesives. I would personally use Mapei Keraquick adhesives but if you are a little inexperienced then something with a longer bucket life would be better, try Keraflex or Keraflex maxi both in white.

 

[wetdec]

I have done the test with the glass of water and no water came out so I suppose 06mm hardie backer boards would be sufficient.
What thickness adhesive should I use?
I was recommended to use Bal SBR OR APD and single part flex as adhesive by an expert on this site, do you mix the SBR/APD to adhesive or apply to backer board ? Is it necessary ?

If its 18mm ply,screwed to sound joists at 300mm centres and as stable as you say you dont need to overboard it with anything wasting money, put a membrane over it and tile............



,
.

 

[mondieu]

Hi again,

My wife has changed her mind :mad2: and we have now brought beige floor porcelain tiles 400mm x 400mm for the upstairs bathroom floor.
As per above, I am laying 6mm backer boards to plywood floor and then tiling on top,is Bal single part flex or Mapei keraflex still good for porcelain tiles ?

Thanks for all you help,