Your local planning authority (LPA) - usually the district or borough council - is responsible for deciding whether a proposed development should be allowed to go ahead.

This is called planning permission. Most new buildings, major alterations to existing buildings and significant changes to the use of a building or piece of land need this permission.

To make a detailed planning application for development, excluding householder developments.

For example:

• Any works relating to a flat

• Applications to change the number of dwellings (flat conversions, building a separate house in the garden)

• Changes of use to part or all of the property to non-residential (including business) uses

• Alterations to a non-residential building

• Replacement dwellings

For proposals to alter or enlarge a single house that doesn’t fall under permitted development. It should be used for projects such as:

• Extensions that don’t fall within PD

• Some rear dormer loft conversions (in a Conservation area, AONB or SDNP)

• Front dormer windows

• Garages, car ports and outbuildings forward of the front wall of the house or that don’t comply with the PD guidelines

Planning permission is not needed for all household building work. Under permitted development rules you can carry out a number of household building work projects, provided they meet certain limits and conditions. The main types of permission required for works to an existing house are householder planning consent and full planning consent.

Planning permission is no longer required by the majority of homeowners for most loft conversions, rear extensions and single storey side extensions as long as they are within certain limits. These limits are usually about the height, width or depth of the extension / dormer or whether the property is situated in the South Downs National Park (SDNP), Conservation Area or Area of Outstanding Natural Beauty (AONB). For any development that is deemed as PD we will always apply to the council for a Certificate of Lawful Development to obtain written approval that the proposal complies with the PD rules. PD extensions are only allowable if they are attached to the original side or rear wall of the property.

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More information can be found on the Planning portal website.