Building regulations will be required for a conservatory or extension if:
The internal floor area exceeds 30 cubic meters.
The conservatory is to be built on any level above ground floor.
The roof of the conservatory/extension is less than 75% translucent i.e. glass or polycarbonate.
The wall area of the conservatory/extension is less than 50% glazed.
There is to be no physical barrier of external quality separating the conservatory/extension from the original dwelling i.e. window, door or walls.
A heat source which is attached to the main house system is being installed (Any heating system in an exempt structure should have separate temperature and on/off controls).
Glazing and any fixed electrical installations in a conservatory should comply with the applicable building regulations (see below).
Any new structural opening between the conservatory will require building regulation approval, even if the conservatory itself is exempt.
If the physical barrier i.e. window, door or wall between the conservatory and original house is to be removed, as part of building control approval a SAP test (Standard Assessment Procedure) will be required.
NB: If you have any doubts regarding building control compliance you should contact your local building control department.