On Wed, 21 Jul 2010 16:13:53 +0000, AL_z wrote:

I'm installing a new bathroom in my house. One of the jobs is to tile
the walls adjacent to the bath, as I'm going to install a shower
attachment.

One of the walls seems to be made of thin (8mm or 10mm?) plasterboard.
On that wall, I'll be fixing a shower attachment holder. Is it OK to
stick the tiles directly onto the plasterboard? Or should I face the
plasterboard with say chipboard first, to increase the rigidity and
strength?

That doesn't sound very thick, given that it's a shower wall that might
get bumped by elbows; I'd go with the thickest wall you can get in there
(it's preferable to go with one piece; fixing one thin layer to another
won't be as rigid as just going with one thick layer in the first place -
but I appreciate that you might not want to rip the wall down :-)

This side of the pond they do a cement backer-board for tiling onto
(often branded as wonderboard) - I'm not sure what the equivalent is in
the UK. Some moisture will get through the tiles, so it's better not to
use chipboard as the backing - plus the bond between tile and wood isn't
always as strong as tile and cement, and you don't want tiles falling off
in a few years (probably).

The cement stuff's more expensive than chipboard here, but still less
than equivalent thickness of ply.

Also, should I use a special waterproof adhesive and waterproof grout
with the tiles, or is the regular stuff considered OK for shower areas?

Hmm, not sure. You might be OK with regular stuff and some grout/tile
sealer, but personally for a high-moisure area like a bathroom I think
I'd just use the waterproof stuff to be sure.

The tiles I bought are 300 x 250mm granite effect tiles which are almost
twice as thick as the average small 150mm square wall tiles. So they do
have a lot of rigidity and strength of theor own.

I'm not sure it makes much difference; it's still essentially a lever if
put onto a less-than-rigid surface, and any flex at all could weaken the
bond or cause grout lines to fail.

cheers

Jules