Hi, thank you for your reply, The house and integral garage was built in 1987 with the garage space being used as a bedroom in 1990. The same building regulations applied at the same time as both were carried out. At this period there was no requirement for insulation under the ground floor to the house in any part. There was no requirement for insulation to the cavity wall in any part of the house. A minimum of 100mm of loft insulation was required for the loft area.My neighbour was the head of building control for this area at the time and he says that as the garage is integral and part of the building envelope it was not exempt from building regs at the time.so the garage part of the house was built to the same requirements as the rest of the habitable house. Electrical lights and sockets were installed at the build stage.So how would it not be classed as a habitable space ?. Would be grateful to hear your thoughts