I have removed tiles and most of the plaster has come away. It is an old brick wall, looks like grey cement wall at the back. I have large patches of up to 2-3 mm deep. How should I approach this ? Do I need a Bonding Plaster 1st and then a top finishing plaster ?
Answer Hi Pat Yes level the patches out with bonding coat. Make sure the edges are damped down with water or PVA to ensure the suction is not too great - if it is high suction then the bonding coat will shrink and crack away. Flatten whole wall within a few millimetres and then skim as normal.