Looking for advice in case I make another mistake. Had East European builders in who did a couple of bothch jobs, one being my shed. They said they dry lined it, but they just stuck the plasterboard to the blockwork. Now there is a lot of mould and getting worse on two walls. Outside two walls of the original shed were not plastered and are just bear blockwork. Had a builder look at it and he gave me a good price to redo it, but not sure whether it's worth it. He intentds to plaster the two unplastered walls outside, inside he intentds to dry line the walls using 'felt' and then I think, he said 'aertex' for insulation, also putting in two vents - there are no vents in the room at present. Is this the correct procedure. I have had such hassle with the shed I am thinking of just removing the plasterboard, exposing the blockwork again and just using the shed for washing machine and dryer as it was used previously, rather than as an office space, which I would like as we are currently stuck for space in the house. Any advice greatly appreciated.