Exempt buildings from Local Authority Building Control

Exempt Buildings

Some buildings and extensions are exempt from the Building Regulations. These include small garden sheds, detached garages, conservatories and porches. In all cases certain restrictions on size, use or construction apply.

The following information has been provided to help you decide if your building works are exempt:

The completion and return of our Exempt Buildings form will allow us to provide you with written confirmation that your proposed building work is exempt or not. There is no requirement to submit this form, however, our experience has shown that written confirmation that works are exempt can be useful and save time when the property is being sold.

You are advised not to construct conservatories where they will restrict ladder access to windows serving rooms in the 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.

Electrical Safety (Part P)

With a few exceptions any electrical work undertaken in dwellings, which includes the addition of a new circuit, or involves work in a kitchen, bathroom or garden area must be notified to Building Control. For further details see Approved Document P.

Part P, electrical safety

Glazing for Conservaties and Porches

Any glazing shown in the shaded areas of the diagram below needs to comply with Approved Document K, for the proposals to be considered exempt.

Glazing for conservatories and porches

Types of exempt building work

Certain buildings and extensions are granted complete exemption from the Building Regulations, these are listed below:

Class 1 - Buildings controlled under other legislation. For example, Ancient Monuments and nuclear power stations.

Class 2 - Buildings not frequented by people. For example, detached building housing plant, only visited for maintenance.

Class 3 - Greenhouses and agricultural buildings. Greenhouses provided they are not used for retailing, packing or exhibiting. Agricultural buildings, for example, a barn used solely for keeping animals.

Class 4 - Temporary buildings. For example, a marquee erected for a show or exhibition.

Class 5 - Ancillary buildings. For example, huts on a construction site.

Class 6 - Small detached buildings. See diagram below.

Class 7 - Extensions. See diagram below. In addition to this, other criteria is applicable to conservatories and porches.

Types of exempt buildings

Criteria for an extension, used as a conservatory, being exempt from the Building Regulations

Schedule 2, Exempt Buildings and Work, Class 7(a)

Background: Over recent years the public perception of what can be termed a conservatory has changed. The Oxford Dictionary (1990) defines a conservatory as "a greenhouse for tender plants" and in particular "one attached to and communicating with a house". The Building Regulations, Approved Document L1, Section 1 (1.58) states that "a conservatory has not less than three quarters of the area of its roof and not less than one half of the area of its external walls made of translucent material" Since conservatories became exempt under the 1985 Building Regulations manufacturers have exploited this exemption by promoting them for such uses as breakfast, dining and sitting rooms: effectively they are seen as an extension to living accommodation.

Policy: To be considered exempt, an extension to a building for use as a conservatory shall be:

  • At ground level and not exceed 30m2 floor area.
  • Glazed to satisfy the requirements of Approved Document K of Schedule 1.
  • Physically separated internally from the building it is attached to, for example, by a door.
  • Without sanitary appliances.
  • Not intended for year round habitable use.
  • Used to some extent for the propagation of plants.

Note: All other extensions used as a conservatory are fully controlled under the Building Regulations, as are all conservatories erected in conjunction with a new build house.

Criteria for an extension, used as a porch, being exempt from the Building Regulation

Schedule 2, Exempt Buildings and Work, Class 7(a)

Background: Since porches became exempt under the 1985 Building Regulations owners and developers have exploited this to cover a wide range of extensions. The Oxford Dictionary 1990 defines a porch as "a low structure projecting from the doorway of a house and forming a covered entrance".

Policy: To be considered exempt, an extension to a building for use as a porch shall be:

  • At ground level and not exceed 30m2 floor area.
  • Glazed to satisfy the requirements of Approved Document K of Schedule 1.
  • Positioned over and physically separated from the building it is attached to by a door.
  • Without sanitary appliances.

Please note that Planning Permission may also be required for your proposed building work. Therefore you are advised to contact your local Planning Department, to seek their comments.


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