Foam boards on uneven brick

[MICH43L]

Looking at options for tiling a bathroom 2.3M(L) * 1.7M(W) * 3M(H)

For the floor looking at replacing old uneven boards with 25mm marine ply (and sealing).

I think the walls already have tile-on-tile, so going to take them back to what I'm sure will be pretty rough/uneven brickwork.

Was going to use plasterboard with aquapanel in the wet areas but came across 12.5mm foam boards (marmox / wedi / jackoboard) which look good. It's a well-used room that gets fairly wet, so thinking of using these boards throughout.

Anyone have any experience of these?

Seems like I'd just clean up the brick and dot and dab them on with tile cement before drilling through and mechanically fixing with large washers once set. (Nice to avoid battening and helps with being able to set plumb and square).

Do you seal the brickwork first?
Would you use battens infilled with insulation on the exterior (cold) wall? Or maybe get thicker foam boards for this wall?

(Edit: Battens might be good here to give space to run pipework).

Any other pointers welcome.

Cheers

 

[JaimieH]

For your floor personally I wouldn't tile directly onto any wooden substrate, even marine ply. I'd fix 22mm P5 moisture resistant chipboard and overboard with 6mm No More Ply or Marmox boards. Alternatively you could lay 22mm No More Ply tongue and grooved boards straight onto the joists and avoid any overboarding. Either of these methods would be preferable to me than tiling on marine ply. Marmox boards are brilliant to use and an excellent choice for tiling onto. Yes, prime the brickwork/blockwork with a tilers primer first and tape the joints after mechanically fixing. You could build a stud wall to hide the pipework if you want, 400mm centres for 12.5mm Marmox or 600mm centres for 20mm. Always use a powdered cement based adhesive not a tubbed one. Good luck.