Advice on shower install

[Oakamoor]

I've had first fix done on a bathroom renovation, my plumber advised I tank the walls before tiling, but I'm concerned about the walls.

The area behind the shower used to house a water tank and lots of the plaster is shot, surely this is not a good idea to tile on top of?!

I will be removing any loose plaster and if lots wants to come off I presume I should re-board. Which leads me to my main question, should I be looking at water resistant plasterboard or Hardy or other, and if so, is dot n dab enough to hold the weight of tiles, or should I be looking at mechanical fixing into the brick?

Photo of area behind shower is attached. It will be 900x1200, combi boiler fed, resin tray with R2 shower.

Thanks in advance for any advise!

 

[Wobblerobert]

Definitely use some sort of board if plaster board sound cover with 6mm HariBacker boards or do as I am doiong rip off old plasterboard amd screw on 12mm Hardibacker board only (.99 +vat tis month at Selco. tape all joints and onto tray and apply Everbuild aquaseal rubberised membraneover tapes stick tra to wall with CT1 and run abeed along tray leave 2mm gap to tray to Silicon for belt and braces waterproofing

 

[Ben-gee]

Yes remove all the plaster if shot.
Yes dot and dab plasterboard adhesive is adequate - remember to have a continuous horizontal bead of adhesive at floor and ceiling level ( this is for fire safety reasons)
Also remember one or two screws at high level, though a dab, once the adhesive has set - this is to stop the board peeling.

Don’t skim the board.

Then tank it with either a membrane (Impey water guard is my favourite) or a tanking solution - two full coats.