Bexley follows national PD rules — single-storey rear extension up to 4m on a detached house (3m semi/terrace), within 4m height, is PD. Prior Approval covers up to 8m/6m under the Householder Consultation Scheme. Side and two-storey extensions need a full Householder Application to Bexley Council. As a London borough, applications are assessed under London Plan policies as well as Bexley's Local Plan — the London Plan's design quality standards can affect even modest schemes in denser parts of Bexleyheath and Sidcup. Properties in Bexley's conservation areas (Old Bexley, Lamorbey, Bexleyheath Broadway) typically require a full application regardless of extension size.

The Party Wall etc. Act 1996 applies across Bexley as it does nationally. Notice is required if you are building on a shared wall, excavating within 3m of a neighbour's structure to a depth beyond their foundations, or excavating within 6m where a 45° line is undercut. Bexley's London Clay subsoil typically requires deeper foundations than chalk-based areas, which means the 3m and 6m thresholds commonly apply even on modest rear extensions on terrace and semi-detached Bexley properties. We advise on party wall obligations at survey stage.

Bexley's three conservation areas — Old Bexley village, Lamorbey and Bexleyheath Broadway — carry Article 4 directions restricting Permitted Development. Within those areas extensions visible from the highway, roof material changes and new external cladding typically require a Householder Application to Bexley Council. The London Plan's design policies apply borough-wide — extensions must respect the scale, massing and material palette of the original dwelling. Bexley Council's Urban Design Guide sets out expectations for brick colour, bond and window proportions that inform both the planning assessment and any pre-application advice.