Conservatory definition - what is the classification of a conservatory?
As most conservatoires are exempt from Building Regulations provided they comply to a few
basic requirements, the term ‘conservatory’ has been tested many times by other homeowners and house extension
designers or architects in the past that often wanted a hybrid type of house extension using traditional house
extension construction methods but want the freedom of design that a conservatory classification would
Therefore what defines a conservatory? What is a good conservatory definition? As a conservatory is usually a
highly glazed structure for the walls and roof, at what point does a house extension not become a conservatory?
Having experienced this scenario myself with my own local authority, most councils use the test of ‘predominantly
glazed’ . Therefore it could be argued that provided the house extension has 51% or more glazed area it can fit the
term conservatory and therefore become exempt from Building Regulations provided all the other requirements are
This is not a guarantee that all councils building control departments will view it in the same way but it is a
good start and one that seems fair to all sides. If you are in any doubt as your house extension will not be
entirely glazed and has a large area of standard walling or roof them send a copy of the preliminary design to your
Building Control dept. and request confirmation. Some Councils now charge for this informal advice but it is worth
getting it clarified right ate the start of the design process.