best product for plastered wall

[Perfect Tiling]

Evening. I'm currently working in a new house that has a curved shower wall which consists of concrete blocks that have recently been bond coated and skimmed. I used mapie shower waterproofing kit....applied the primer and 2 coats of the tanking over 3 days to allow drying. however....the tanking came off in a skin with the primer. First thoughts are that the plaster was still damp....I'd left it 2 weeks from final skim coat. Could this be the case? Is there a better product to use on plastered walls. I usually use mapie aqua defence straight onto plasterboard...it comes with no primer and sticks like s*$t to a shovel. Much appreciated.

 

[Dumbo]

Some say to water down the first coat so it get a better bond to the plaster, much like mist coating before emulsioning

 

[Dave]

Has the skimming been over polished , might need a light sanding first , then the primer wont skin. Also dont put neat pr360 as it will skin. Water down.

 

[Italy]

aquadefence does not work if there are still moisture residues, better to use mapelastic which is also breathable.