Still only a beginner so loads of questions! Am I correct in saying a bonding coat would be used on a ?? artex ceiling prior to a multi finish skim. Also I have been asked to skim a few walls for a friend. One part of a wall has broken right away (old plaster) sounds like down to brick. Would I use a bonding coat (following PVA on old brick) for this section, then PVA this coat prior to plastering - multi finish- this section?