Good afternoon chaps I’ve just sand cemented a couple walls which had issues with damp , the customer put KA tanking slurry on a while ago , I scratch coated it yesterday & put top coat on today & rubbed it up . My question is what finish coat to put on it . A friend I know who’s an old school plastered very good to be fare said to me British gypsum guide lines recommend to leave it 28 days before applying finish coat . My mate prefers Thistle board finish over multi as it tends to shale if it doesn’t dry out completely . I was going back Monday to skim it . Any advice I’d be grateful. Thx in advance.