Hi. I just joined the forum(s) this evening for some definitive advice and hope someone can help, please. I am installing a new shower cubicle and quadrant tray in the corner of a small bathroom. One wall is rendered and plastered; the other is battened out and covered with 12mm Hardie tile backerboard sheets to hide all the plumbing and electrics. My questions are:

1) after tanking (with a BAL waterproofing kit), is it best or indeed absolutely necessary to use a FLEXIBLE powder adhesive or will the tanking material accept a ready-mixed waterproof/water-resistant paste?

2) As BAL's product information sheet for single-part flexible adhesive advises not to prime or seal tile backerboards, doesn't this contradict their advice to prime all surfaces first with the Prime APD that's included in their tanking kit...?

Many thanks, Den

den.i def would not use pre mixed at all.you will need a flexi powdered adhesive.no call to prime the tanking.you can prime the rest if wanted.good quality adhesive will grip well.i prefer mapei adhesive and grouts.all flexi.

Powdered adhesive will be far better.

The priming is for the tanking kit not the adhesive, do as they reccomend otherwise there will be no come back if anything goes wrong.

Many thanks for two quick responses as I need to start the job tomorrow (Wednesday)!