what would be the the best procedure when putting up 2x2 timber studding/plasterboard walls in a living room where the old mortar walls which had been skimmed over have been damaged by condensation as the mortar is not blown but bubbling and it seems the salts are coming out of the wall or mortar and blowing the skim off in parts there is no penetrating damp as everything looks bone dry even the internal partition walls are bubbling when actually went to see the job you could put your hand on the walls and feel damp with condensation would the new studded walls need venting along with vents in the room the house is brickwork but with only a 25mm cavity the reason why we doing this is they dont want to hack the walls off any advice thanks