Building Regulations approval is required under the following circumstances:
The erection or extension of a building (including loft conversions)
The installation or extension of a service or fitting (e.g. washing and sanitary facilities, hot water cylinders, foul and rainwater drainage, replacement windows and fuel burning appliances)
Alteration works which may have an effect on the building in terms of structure, fire safety and access and facilities for all (e.g. openings in walls, removal of fire doors, changes to accessibilities)