FiscoKing

Thanks for all the replies.

It would appear then that the 'waterproof' designation for cement adhesives is just over-enthuastic marketing.

The BAL people sugested the Mosaic Fix Powder, given that I'm using large tiles (even though it says it's for mosaics), and the blurb says it's good for pools.

I'll get some Wedi board down first.

Thanks.