Plywood Or Cement Board

[zed123]

Hi I have a 200 sq m space to tile , on an existing mezzanine floor. there is slight movement in places not much though.

I am wondering what the experts here would recommend to use prior to tiling plywood or cement board [no more ply ]

any input / advice would be appreciated.

 

[Old Mod]

Hey Zed,
Can u define movement for us please?
Are talking about deflection (bounce)?
Any deflection could potentially be detrimental to your finished floor.
Do you know the construction of the existing floor?
What are you over boarding?
What material is the final covering?

 

[zed123]

it is very minimal bounce in some places , so minimal I should not have mentioned it so you can ignore that.

existing floor - I am not very good with timber but they are 2mx60cm pieces of wood for the floor of mezzanine which has been used for storing stock for 5 years. but now we are going to tile it with 12mm porcelain glazed tiles.

thanks for your reply 🙂

 

[Old Mod]

it is very minimal bounce in some places , so minimal I should not have mentioned it so you can ignore that.

Haha it's hard to ignore something u've said
Well minimal or not, bounce is bounce, and is not conducive to a successful installation.
So strengthening the existing floor is something you should look into.

So if I was to ignore everything u've said apart from the actual question of cement board or ply, the answer would be very simple.
The choice would always be a cement board over ply, ply is not a stable material, it can expand, contract or delaminate and is effected by moisture.
A cement board is an inert material, it doesn't suffer the same problems as ply, but must be installed correctly.
Stagger your joints, glue and screw in place, not forgetting to apply their glue to the edges as u lay the boards, prime with tile SBR.

 

[Just Rizzle]

another alternative could be to use a decoupling membrain schluter ditra then screed over with fiber leveller then tile

 

[zed123]

is tiling onto the existing floor boards not a good option?

 

[zed123]

is there any mapei brand which i could use instead of no more ply?

 

[White Room]

6mm hardie backer glued and screwed.

 

[Dan]

If you replace all the nails for screws you can use fastflex by BAL. I think another firm does a ready made one but can't for the life of me remember who.

 

[zed123]

one guy i have called round is saying to use pva instead of mega strength adhesive to stick the no more ply onto the wood, do you think that is advisable?

 

[mike1979]

Trouble is some people think backer boards are the answer to the entire world and think the prep doesn't need to be done but it does get the bounce gone then the backer boards will reward you I have before now replaced a floor with wayrock and laid uncoupling on top job done

 

[Old Mod]

 

[AliGage]

@RayTheTiler - I'm curious how Ditra would solve deflection.....

@zed123 - How has the mezzanine been created? Are you able to view the underside from below? A chipboard floor spanning 600mm between joists will still have considerable bounce. You could get some noggins in from underneath.

Then over board with a suitable tile backer, glued and screwed.

 

[Lee@emctiles]

And to add to @AliGage comment i would probably use an s2 adhesive too, like TileMasters Ultimate.