We have recently converted the loftroom above our garage into a self-contained studio and we have built-in cupboards into the eaves down each side. While the main room has been plastered and decorated, the insides of the cupboards have the roof timbers on the sloping sides exposed. There are sheets of polystyrene insulation material in between each of the timbers (with about a two inch gap between these and roofing felt), but there is a terrrific draught coming up from where the external soffits/cladding overhangs on each side of the garage. I'm thinking of stuffing some loft insulation down into the gaps from inside the cupboards, before boarding the internal sloping sides (we have already boarded the floor). (A) Will this cause lack of air circulation and/or build up of condensation? (B) Does anyone have any other ideas of insulating the sloping sides of the cupboards - I had thought of using some kind of reflective polystyrene sheeting, like the stuff you use under laminate floors, but not sure if this would be sufficient? Ta.