Hello I'm a novice diyer and need some advice regarding replacing the plaster board ceiling in my extension. The property has a 2 story extension (40 years old) which is 1.8mx4m and has a felt flat roof which I can't get on top of to inspect. There appears to be a condensation problem all around the joint of ceiling to wall. I have poked a hole to check above the old plaster board and there is no insulation, which explains why its freezing in there. It appears to be a cold deck construction but the plasterboard has a moisture barrier but from the outside I cannot see if there has any cross ventilation in the construction.\n\nMy questions are what is the best way to go about insulating the ceiling and reducing the condensation recurring. Should a vcl be used and if so what material and how should it be installed. I don't have the budget to get someone in so will be doing this work myself.