Out-Law Guide 4 min. read

Permitted development rights: upwards extensions


Developers in England will be able to make use of permanent rights provided for in regulation to add storeys to certain types of buildings to help meet the growing demand for new housing.

The regulations amend the Town and Country Planning (General Permitted Development) (England) Order 2015 (the GPDO) and will also make it easier for developers to extend existing homes, providing additional space for families. The government hopes the new rights will lead to a wider range of development and speed up the delivery of housing.

Right to construct new homes on detached blocks of flats

The Town and Country Planning (Permitted Development and Miscellaneous Amendments) (England) (Coronavirus) Regulations 2020 came into force on 1 August 2020.

These amended regulations introduce a new Class A into the GPDO – 'New dwellinghouses on detached blocks of flats' – which grants the right to extend purpose built blocks of flats upwards by two additional storeys. The blocks of flats must consist of three storeys or more before the extension and cannot have a total height of 30 metres or more with the additional two storeys.

Right to construct new flats above certain buildings

The Town and Country Planning (General Permitted Development) (England) (Amendment) (No. 2) Order 2020 amend the GPDO and grant additional permitted development rights which take effect from 31 August 2020.

Four new permitted development rights, Classes AA-AD, are introduced into the GPDO. Each class allows work for the construction of one or two additional storeys, consisting of new flats, built on top of the highest existing storey of certain buildings.

Classes AA and AB permit new flats on detached buildings and terraced buildings respectively which are in commercial or mixed use as shops, for financial and professional services, restaurants and cafes, offices, betting offices, pay day loan shops, or launderettes or in a mixed use combining one of those commercial uses with use as a dwellinghouse. For Class AA only, the building must already be three storeys in height, above ground level, to rely on the permitted development right.

Classes AC and AD permit new flats on terraces or detached buildings respectively which are in use as single dwellinghouses. In both cases the right is not permitted if the house has already been enlarged by the addition of one or more storeys above the original structure.

Prior approval requirements for Class A and Classes AA-AD

The new rights are subject to prior approval from the local planning authority and so an application must be made in each case. Matters which the local authority will consider include potential highways impacts; impact on neighbour and occupier amenity, including the extent to which the development would overlook others, invade privacy or curb natural light on other property; the external appearance of the building; the provision of adequate natural light in all habitable rooms of the new homes; the impact of noise from existing commercial premises on the intended occupiers of the new homes; impacts a taller building may have on air traffic and defence assets; and the impact on protected vistas in London.

Local planning authorities are required to consult certain persons or bodies where specific impacts are identified. For example, where the local authority think there will be increased traffic as a result of the development, it must consult the relevant highway authority. Prior approval applications must be refused where inadequate natural light is provided.

The local planning authority is required to make a decision on an application for prior approval within eight weeks. If a decision has not been made within eight weeks there is a right of appeal to the planning secretary in England for non-determination of the prior approval application.

Conditions and limitations applying to Class A and Classes AA-AD

Each new permitted development right is subject to very specific conditions and limitations which must be carefully considered in each case. There are some common conditions which apply to all five classes:

  • the new dwellinghouses that are constructed must be flats;
  • the new rights only apply to buildings constructed between 1 July 1948 and 5 March 2018;
  • the rights will not apply to buildings in conservation areas or listed buildings;
  • engineering operations within the existing curtilage of the building to strengthen existing walls and foundations and to install services are permitted, along with replacement or installation of additional plant, construction of safe access and egress and construction of ancillary facilities if needed;
  • before development begins the developer must provide the local planning authority with a report for the management of the construction which sets out proposed construction hours and how adverse impacts of noise, dust, vibration and traffic on occupiers and adjoining owners will be mitigated;
  • the development must be completed within a period of three years starting with the date 'prior approval' is granted, and;
  • every dwellinghouse in the building must remain in use as a dwellinghouse and for no other purpose, although uses which are ancillary to the primary use as a dwellinghouse will be permitted.

Extending existing homes

In addition to the new rights, The Town and Country Planning (General Permitted Development) (England) (Amendment) (No. 2) Order 2020 also introduces a new Class AA – 'Development within the curtilage of a dwellinghouse' – within Part 1 of Schedule 2 of the GPDO. This enables homeowners to extend existing homes by up to two additional storeys on a two, or more, storey home and one additional storey on a one storey home. The rights are subject to detailed conditions and limitations.

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