I was looking at buying a house which has had a spiral staircase fitted to access the loft. the opening in the floor is about 4ft so i am assuming they have cut a number of ceiling joists in order to fir the stairs. i have been informed that there is no building control for the work as the loft conversion does not form habitable accommodation. I an concerned that the alteration might have affected the structure of the roof. It is a cut roof with perlins supported on the external party and internal wall. Can anyone give me advice on whether this is likely to be an issue or what kitchens i should be asking. thanks