So I was always under the impression that one aspect required to make "conservatories" exempt from Building Control involvement was that the roof had to be 75% or more glass. However there are now a lot of " solid roof" systems available for new build or as replacement roofs. If a planed conservatory satisfies other criteria such as separate heating and external grade doors separating it from the main house then do the translucency requirements no longer apply? Obviously a number of slid roof system companies suggest they don't!