Single-storey rear extensions are Permitted Development for most Kent properties — up to 4m deep on a detached house or 3m on a semi-detached or terrace, within 4m ridge height, and not wider than the original house. Larger rear extensions up to 8m (detached) or 6m (semi/terrace) require Prior Approval from the relevant district council. Side extensions and two-storey extensions need a full Householder Application. Kent's district councils — Maidstone Borough, Canterbury City, Tonbridge & Malling, Sevenoaks, Medway Council — each handle applications for their area. Conservation area and listed building properties typically lose Permitted Development rights regardless of size. We advise on the correct route at quotation stage.

The Party Wall etc. Act 1996 applies across Kent. You must serve notice on adjoining owners if you plan to build on or cut into a shared party wall, excavate within 3m of a neighbour's structure to a depth greater than their foundations, or excavate within 6m where a 45° line from the base of those foundations would be undercut. For most single-storey rear or side extensions attached to a shared wall, at least one notice is required. We flag party wall obligations at survey stage and can recommend a qualified surveyor if a Party Wall Award is needed.

Yes — Kent has an unusually large number of designated areas where Permitted Development rights are reduced. The Kent Downs National Landscape (AONB) covers much of Sevenoaks district and parts of Canterbury, where district councils expect extension materials to match local character. Conservation areas across the county — Canterbury's World Heritage buffer zone, Rochester Cathedral precinct, Chatham Historic Dockyard, Tunbridge Wells, and many village conservation areas — carry Article 4 directions requiring a full Householder Application for works that would otherwise be PD. Listed buildings always require Listed Building Consent. We check the relevant district council conservation map before quoting any project near a designated boundary.