best tile backerbaord to pack out wall for mosaics to come flush with cermaic tiles

**jonnyc** · 22-01-2011

just starting some bathrooms where I will be tanking the plastered shower walls with mira 4180 and multicoat.
bottom half will be 4mm glass mosaics with 1mm bed.
top half will be 9mm ceramics with 4-5 bed .

both tiles must come flush to each other where they meet.
need to make up the difference between 5mm mosaic with adhesive and 14mm ceramic inc adhesive.
so i have 9mm for backerboard and adhesive.

anyone know of a backer board thats approx 6mm thick plus 3mm flex adhesive to stick to multicoat that is flat and does not bend like insulation boards.
hardi backer ,or aquapanel cement boards ideal as rigid but only come 12mm i think.

thanks