Internal painted brick

[stolen stilton]

Internal cottage wall currently painted brick. Customer has got hold of some dri-coat he wants me to render it with and then skim. Whats the best way of achieving the key? Just grind the walls all over which i dont really want to do because of the mess or could I just WBA it first thing and float straight on top once this has dried? Or do I paint a sand/cement/pva slurry on it?

Cheers all

 

[lucius]

Microgetis you will be told.