On Thu, 07 Feb 2008 13:21:53 GMT, DavidM
wrote:

I'm about to put ceramic tiles onto the splashback behind the kitchen
worktops, up to the underside of the cupboards. Currently there is
18mm standard (ie not external grade) ply boarding securely fixed to
battens on the wall, and I'm planning on tiling straight onto the ply.

All the "tiling onto ply" advice I've found on google is about floors.
Flexing under load isn't going to be my problem, just want to make
sure the tiles stick, although tile adhesives for wood all seem to be
the flexible sort anyway. There's conflicting views on to PVA or not
to PVA the ply first. To my mind, why PVA seal the surface first when
you want the adhesive to "soak in" a bit before it sets (or
crystallizes) to get good adhesion, but there may be something I'm
missing.

Any views?

David.
Thanks to everyone, very helpful.
David.