Porcelain Equivalent Of Black Quartz Stardust

[berilac]

rapid flex or max flex I think

 

[J Sid]

Plywood.....really?

 

[Dave]

rapid flex or max flex I think

You better get him to check suitability for resin quartz tiles... And as above , as a personal preference , i'd not use ply .

 

[berilac]

you mean which adhesive is suitable?

Also if not ply what would you recommend?

 

[J Sid]

What is the substrate your tile wants to fix the ply to?

 

[berilac]

It's an Edwardian house , bathroom is on the first floor , no idea what substrate but unlikely that it's been changed

 

[J Sid]

Hardie board / no more ply, glued and screwed. But not ply

 

[berilac]

Ok thanks will work with that , are the remaining items pretty much standard

 

[J Sid]

Spacers bigger the I would use, but that's your choice.
And as @Dave say's, check the adhesive

 

[gamma38]

I thought 4mm was a bit big also, ply maybe if he is getting rid of the floorboards to give a better substrate but i would then over board the ply with hardie or similar.