Hello All,

I'm at my wits end - and this post is a sanity check on what I have so
far to rectify the problem.

I've tiled the bathroom - the last two parts to tile are 18mm marine
ply for a boxed section, and 18mm flooring-grade chipboard, both in a
vertical plane.

Tiling on the ply failed. So I tried PVA. This also failed. Then I
tried spirit based undercoat for wood - the tiles were easily removed
with a screwdriver.

The adhesive is a general adhesive & grout from Unibond. The adhesive
after being allowed to set turns into a powerery substance and is
easily removed from both the wood and the tile. The adhesive works
perfectly on any other surface (testament to the 160 other 6'x4' tiles
already up).

My theory is this - the spirit based undercoat still isn't acting as a
barrier between the cement and the wood. My current course of action
is to add another coat of primer, then top-coat with at least one
layer of spirit-based gloss.

Having checked the archives, another avenue is to try a flexible
cement based adhesive.

Is there anything else I should do or try? I need to get this sorted
pronto before my wife leaves me for someone more DIY orientated.

Many thanks!
--
Steve