got an ensuite to tile the customer wanted to do the prep himself to save on cost , however instead of using a proper tanking system like i told him to he went and used liquid rubber used for sealing roofs .

anyone know of an adhesive that will stick to liquid rubber, rang bal and they said nothing will stick to it.

I think Bal answered your question.

Gotta love customers eh ? ....No

That's incredible....I haven't heard that one before. I'm almost certain no manufacturer will approve that. Trouble is it puts you in a spot. I suggest you have him call BAL himself if he doesn't believe you. Or you call BAL again with him present.

The reason is it flexes on roofs

I had a job to price a couple of months ago, when I went to do the survey (just a domestic bathroom) the walls had been nicely sanded down, to remove old emulsion and bits of adhesive residue. All good I thought, then I noticed a sheen on the wall. The customer informs me, to save me a job, he has already put PVA on the walls.