have just had a room plastered and we have a damp patch in the middle of a corner wall - one wall is external and the other internal have taken bricks out from outside to check if damp or wet in the cavity and all is dry - the patch will dry out and then return and dosent get any bigger have put a coat of paint on the wall and it sticks ok but stll the patch returns what could it be
Also was the patch evident prior to the replastering, and what kind og plastering was carried out, a single skim over existing plaster or full hack off and two coats (base and finish). If so, was the plaster lightweight gypsum or sand and cement ?