Ok. The floor is joists with 150mm mineral wool suspended on Netlon covered with 22mm Caberboard. The ceiling & walls are covered in 12.5mm Gyproc with 37.5mm Polyfoam Plus bonded. The room is NW facing. One wall has a 3.5m X 2.1m window in Meranti hardwood. It is glazed with 6mm toughened...