Preping bathroom floor for tiling?

[Moonshine]

Looking to prepare my bathroom for tiling, at the moment it's just the caberdek floor with protective covering.

What's the best way to prep this ready for tiling?

[Nickfromwales]

1 hour ago, Moonshine said:

Looking to prepare my bathroom for tiling, at the moment it's just the caberdek floor with protective covering.

What's the best way to prep this ready for tiling?

6mm plywood, glued and screwed at 120mm centres max. Dampen the ply with a 50/50 mix ( primer / water ) immediately before applying the adhesive.

Assuming the deck is already glued and screwed with at least 5 screws per joist per board? And zero movement?

I use Ultra or Bal for primers and adhesives.  Mapei is also very good.

[nod]

You can stick Ditra mat direct onto the deck 

[Moonshine]

10 minutes ago, Nickfromwales said:

6mm plywood, glued and screwed at 120mm centres max. Dampen the ply with a 50/50 mix ( primer / water ) immediately before applying the adhesive.

Assuming the deck is already glued and screwed with at least 5 screws per joist per board? And zero movement?

I use Ultra or Bal for primers and adhesives.  Mapei is also very good.

 

What about 6mm tilebacker / cement board?

 

Slight concern with screwing boards down is the is ufh pipes underneath on alu clip, so will only want to use 20mm screws

[Nickfromwales]

1 hour ago, Moonshine said:

 

What about 6mm tilebacker / cement board?

 

Slight concern with screwing boards down is the is ufh pipes underneath on alu clip, so will only want to use 20mm screws

Cement board way too brittle and a pig to install as it needs to be pilot drilled, countersunk, and bonded down with adhesive then screwed. Completely overkill. I have only ever laid cement board under tiles when installing / creating bespoke wetroom shower floors from scratch.

 

Yes, correct size of screw is assumed. I use 20mm screws for 3.6mm ( aka 4mm ) ply, and 25mm screws for 6mm ply. You need to be putting all of your weight on the impact drill when screwing these in, or they'll just hit the ply and spin out ( 20mm screw vs 6mm ply ), so go with 25mm screws as they'll still be 3mm shy of the pipes when the heads are flushed with the top of the ply. Set the drill speed a bit slower to avoid any "whoops" moments   Less haste, more speed etc etc.

 

 

Edited January 18, 2023 by Nickfromwales

[nod]

I do dozens of bathrooms with Ditra Matt glued down Absolutely bombproof 

Or if your not bothered about the build up A 10 mil insulation or backer board bedded on adhesive then screwd down the following day works well 

Most of the site bathrooms we do don’t want a step 

[Moonshine]

Not come across the ditra Matt product before I will look into it, expensive though

[Thorfun]

1 hour ago, Moonshine said:

Not come across the ditra Matt product before I will look into it, expensive though

we're a long way away from tiling but from what i've read on the tiling forum here it's very well thought of and used often. apparently it is expensive but worth it. so it's on my list of products to consider and to talk through with the tiler when we get there.