a freind of mine has just brought a house close to me ,the strange thing is 2 of his interier walls look like they have been rendered inside . the fact is a large patch on the wall looks like its about to fall off. if we pull down the large ugly patch can we use a bonding coat over the affected area then skim over as if we was doing patching work as it looks like the rendering has gone on to plasterboard .
furthermore once you pull down an old mix without damaging the other area's of the wall can you apply a fresh mix ,or has the hole board got to be replaced . i know it sounds strange but ive not seen anything like this before .
all advise is most welcome
rnd