Peter Taylor wrote:

"Kalico" wrote in message
...

Please can anyone tell me what they think the best board to use behind
the tiles of a shower?

Wedi board
http://www.wedi.co.uk/flash.htm
It's lighter and easier to cut and fix than Aquapanel. Might also be
cheaper.

Or similar, hardibacker, and several other trade names for
fibre-reinforced cement-faced foam board. Most useful property is that
it is waterproof, being made of plastic, rather than just
water-resistant. So with a tanking kit you can ensure that the shower
is waterproof irrespective of the integrity of the grout and tile
cement. Aquapanel will let the water through, it just won't
disintegrate like plasterboard.