Preparing bathroom floor for marble tiles - not convinced of plumber's solution

[achillea]

Hi

I'm currently having my bathroom refitted. The old floorboards are very creaky, there is some movement and the boards are all in small pieces. I am having UFH and 50 x 50cm marble tiles fitted. My plumber is intending to put 9mm ply onto the floorboards then lay UFH directly onto of that. I'm no expert but I'm worried that the 9mm won't sort out the movement which will then lead to my rather expensive marble tiles cracking at some point.

Do you think his solution is going to be ok or should we take up the old boards and fit something like 25mm ply or just put a thicker ply onto the existing boards? The plumber also says we don't need tile backer boards as the ply will be sufficient.

He is also not planning on tanking or lining the walls for tiling (around the shower bath) - walls are being skimmed then he is planning on tiling straight onto that (6 inch ceramic tiles from Original Style).

Any advice grateful received!

A

 

[achillea]

Thanks - that all sounds sensible. Thanfully the plumber isn't doing the tiling - just preparing the floor. His tiler mate is 30 years in the business but I would have thought he would have given him a better steer on how to do the floor. I think this guy is good at general plumbing but not experienced in complete refits. I shall insist on thicker ply and backer boards! ta.

 

[bugs183]

There are plenty of posts here about how to apply the backer boards.
You'd be amazed how some trades with all the experience in the world havn't caught up with modern methods. I'm sure he's a very good tiler, but maybe stuck in his ways a bit.
You won't go wrong using the strenghtened floor and backerboard.

 

[Martyn Leeds]

I would be asking the tiler directly what's his plans and methods are - and then decide if things sound right..

By letting the plumber have a bash at the prep work, doesn't fill me with much confidence (from the info in your posts)

 

[John Benton]

If the tiler has told him to prep the floor like that, I would be worried as to whether your marble will be fixed to the standard you require. You don't have to have the tiler the plumber recommends! If it's not too late it would be worth getting an alternative quote along with what floor prep and procedures would be carried out.

However, if you do carry on with these guys don't forget to ask questions during the install as to why they are doing this and that and why that adhesive etc. You can always ask the questions and be guaranteed the correct answers from start to finish!

 

[jjoc]

exactly what the other guys have said - 30 years in the business doesnt mean he's an expert if he's not willing to move witht he times! that sounds like poor prep for a marble floor. I'd want ply, backerboards and ditra matting for the UFH.
Tell the tiler your concerns before he starts fixing the stone.