A variety of sites - such as this one - claim that the minimum ceiling height after a conversion must be 2.2m due to building regulations.   What happens if my loft is 2.1m and I ... insert a bed and some wallpaper anyway?   - Will I not (officially) be allowed to call it a livable bedroom? - Will I not get permission to change any external features - windows or dormers etc (If I keep all works internal I don't have to even apply for planning I think?)? - Or is it a