I am helping my bro in law to fit a new bathroom in his house. The floor tiles are 300x300, the wall tiles are 600x300. 3 of the walls are brick and plaster, 1 is stud with plasterboard, I was thinking of using Bal singlepart flex, does that sound ok to you? Also, what size of notch would you recommend on the trowel please?
The floor is floorboards on joists. I have been advised by the shop supplying the tiles to first fix hardibaker boards on to the floorboards with a flexible adhesive and screws, then a waterproof matting fixed down with flexible adhesive (we are fitting a wet room type shower) Does this sound ok to you? I've only heard of ply being used on floorboards before. We're putting in underfloor heating also, would Bal single part flex be good enough for the job?
Any advice would be gratefully received as my bro in law is bigger than me and I don't want my legs broken.

What tiles are you fixing

ceramic,porcelain,travertine,limestone etc..what are the tiles made from?

are any of the walls painted?

have you considered a wet room floor former?


what type of UFH are you putting in?

how thick are the tiles?

answer these questions and we can help you out.

The tiles are porcelain at 9mm thick, the wall and floor tiles are the same material and thickness. We will be using a wet room floor former. All of the walls have been previously tiled halfway up then wallpapered to ceiling, the stud wall is plaster and lath, we are replacing that with plasterboard. The underfloor heating is by Warm-up and is just the loose wire type (not matting.)
Thanks for your quick responses.

trowel 10mm but back skim the tiles to fill any of the profiles, clean off any paint or wallpaper then wash any paste off.
As your using the single wire which is taped down and hopefully a small floor would'nt worry about slc, if it's a large floor then slc could be used.
Prime any bare plaster, not pva.
http://www.thetilesource.co.uk/wall-...-square-metre/

same as whitebeam from me, the hardiebacker is better than using ply, altho you may need to put some extra noggins in your floor joists

Thank you for your replies, I shall noggin the joists. It's a while since i've done any tiling and things seem to move along fairly quickly regarding materials.