I'm renovating a 1920's semi-detached house. The plaster on the walls was slapped straight on the wall about an inch thick, and the ceilings were lath and plaster which had been overboarded. Most of this needs to come off to do repair work to the walls. I want to know what is the best way to insulate the walls and ceilings with the aim of meeting the BC regs u value. ( i believe this is 0.3 [unit needed])
All exterior walls are 9 inch solid brick. The floor joists are 30cm apart with pine floor on top which I don't plan to remove as its all sound. I plan to insulate the loft with rock-wool/fibreglass to about 400mm and use sound deadening board on the ceilings and most internal walls.
Above the living room and kitchen are spare bedrooms which aren't really used. I'd like to insulate them so that I'm not heating unused space.
My concerns are:
To insulate external walls with insulated plasterboard would mean building a frame and losing a good 4 inches around each room. It would also create a logistical problem in mounting (future) fixtures to the wall.
I'm also concerned about condensation in the joists if I insulate the ground floor ceilings.