plywood floor

[jimbo]

Is it ok to tile onto 6mm ply which has been screwed down onto 18mm ply. Or should the 6mm ply be put down first and then the 18mm board?

 

[Gazzer]

Why not just use 25mm ply.? But fixing to 6mm ply is a big no no.

 

[grumpygrouter]

Def no fixing to 6mm ply - 6mm hardie yes, ply no!!!

 

[Rad2474]

Why do you want to use 2 pieces of ply? can't you just use the 18mm piece?is it a height issue? then use 24mm.

 

[jimbo]

The floor has already been put down.Would it be ok to tile directly onto a 25mm board that has been screwed directly onto the joists.Or could the 6mm be laid underneath the 18mm board?

 

[grumpygrouter]

Personally, would feel better having 18mm ply and 6mm hardie unless deflection is an issue and you need 25mm ply!

 

[Gazzer]

but if you put the 6mm under then you have to take all the floor up ?

 

[Time's Ran Out]

The issue that I have with tiling direct to 18/25mm plywood fixed to the joists is that it will crack along every 1200/2400mm joint.
Cover the plywood with a 6mm tile backer board and if deflection free - tile!

 

[SandyFloor]

I use a lot of dense high quality wbp 6mm ply for flooring (karndean/amtico etc) and even then I find the occasional sheet delaminating and that's using a relatively dry adhesive. I would never trust 6mm ply when using wet tile cement no matter the quality of the ply.

 

[marbleman]

6mm ply is A NO NO

 

[jimbo]

Can the hardibacker be screwed to the ply without any addy underneath?

 

[The Legend; Phil Hobson RIP]

No mate glue and screw, using flex adhesive imo

 

[Yorkshire Tiling Services]

Prime ply, face ,reverse & edges prior to fixing

 

[jimbo]

Do Hard ibacker make screws of different lengths? Can any type of alkali resistant screws be used?

 

[Scott]

Prime ply, face ,reverse & edges prior to fixing

Depending on manufacturers instructions