Hi, I've just bought the BAL waterproof kit and speaking to the woman in the shop she advised me against applying it directly to the wall as it stands now. At the moment it is just the bonding coat without any finishing coat. I didn't see the point of putting a finish coat on as it will be completely covered over with tiles soon. The finish is smooth, but obviously not as smooth as a finishing coat skim would give. Is it Ok to apply the WP1 to this surface or do I need to skim over first? Cheers, Simon PS. I have read the instructions on the tin, but it does not mention this as a requirement, only that it can be used on plaster\plasterboard and how long it must have been allowed to dry for.