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Check if you need building regulations

2. Exemptions

The building regulations allow some works to be done without an application but it is advisable to contact the building control department to find out if the work to be undertaken is exempt.

The following domestic extensions, subject to a maximum internal floor area of 30m2, are exempt from Building Regulation Control and may be constructed without making an application:

  • detached garages – these must be sited at least 1m from any boundary or be constructed substantially of non-combustible material
  • carports open on at least two sides


Building regulations will generally apply if you want to build an extension to your home.
However, conservatories and porches are normally exempt from building regulations when:

  • they are built at ground level and are less than 30 square metres in floor area.
  • the conservatory is separated from the house by external quality walls, doors or windows.
  • there should be an independent heating system with separate temperature and on/off controls.
  • electrical installations are carried out by a Part P Competent Person.

You are advised not to construct conservatories where they will restrict ladder access to windows serving rooms in roof or loft conversions, particularly if any of the windows are intended to help escape or rescue if there is a fire.
Any new structural opening between the conservatory and the existing house will require building regulations approval, even if the conservatory itself is an exempt structure.

Note that planning permission may still be required and advice should be sought by contacting the planning department.