I am creating a shower that will have one new wall (studwork with a water resistant plasterboard) and two existing plastered walls.  I was intending to retain the plaster and tiling over (using a tiler cos I don't trust getting it right).  Having read some of the comments I am now wondering whether I should hack off the plaster and replace with a suitable water resistant board before the tiling.  Any advice gratefully received.

Thanx

I wouldnt bother using the plasterboard, go for a tile backer board like Aquapanel (£12  for a 1200mm x 900mm sheet)

I always make a point of tanking every single power shower that I fit. It's actually very easy to do, you can buy the Bal WP1 shower kit from any good tilers merchants or Topps tiles!

You firstly paint the walls with Bal Prime APD primer then leave to dry (takes under an hour)

You then paint the acrylic based waterproofer onto all the corners of the enclosure.

Then stick the polyester tape onto the freshly waterproofed corners and then completely paint over the tape and the rest of the enclosure with the water proofer.

The kit is about £60 and takes me about an hour to do an average enclosure.

Also make sure the tiler uses the correct adhesive for the job, too many tilers are still using adhesives that say they are watertight but if you read the small print they are not. I would get a double A grade adhesive for the work. If the guy uses ready mixed then insist on Bal white star, if he uses powdered then suggest Bal single part flexible. Also make sure he uses a flexible grout such as Bal Superflex.