Westminster / Camden
We design rear and side extensions for St John's Wood houses, from single-storey garden rooms to two-storey additions on larger villas. The complete address decides whether Westminster or Camden policy and mapped conservation records apply, so authority, rear building line, neighbour daylight and host façade are checked before the footprint is fixed.
Last updated
The short answer
A rear or side extension may be feasible, but the route depends on the complete address, legal building type, mapped constraints, planning history, measured neighbour relationship and design. Confirm Westminster or Camden and test permitted development or the application route without predicting approval.
Planning at a glance
St John's Wood
| Local planning authority | Westminster City Council or London Borough of Camden — confirm the exact address |
|---|---|
| Postcode districts | NW6 / NW8 |
| Likely approval route | Householder planning application or permitted development, depending on conservation status, listing and property type — confirmed for the exact address before drawings begin |
| Statutory determination time | 8 weeks for most householder applications (13 weeks for major applications) |
| Local planning note | St John’s Wood and NW8 are place and postcode descriptions, not local-authority or conservation-area boundaries. Confirm the complete address and application site before using council material. For a Westminster site, use the City Plan 2019–2040 (2026), current policies map and the mapped conservation-area, Article 4, listing, tree and planning-history records. For a Camden site, the Camden Local Plan 2017 remains current; the Proposed Submission Draft is still at examination and must not be described as adopted. Use Camden’s mapped conservation-area appraisal, Article 4, listing, tree and planning-history records for the exact site. Westminster and Camden maintain separate St John’s Wood conservation records, so do not infer one designation or adoption date from the neighbourhood or postcode. Westminster’s city-wide basement Article 4 direction came into force on 31 July 2016; Camden’s borough-wide basement direction was adopted on 1 June 2017. Other Article 4 controls are address- and operation-specific. Westminster’s basement policy and Code of Construction Practice and Camden’s Policy A5 and Basement Impact Assessment process are separate. Planning permission, listed-building consent, title or landlord consent, Building Regulations or BSR approval, Party Wall procedures and tree controls remain separate. |
| Typical drawing package | £2,250–£3,250 inc. VAT, fixed fee. Find my package → |
A rear-extension study starts with the existing rear building line and measured garden. The useful question is how the proposed projection affects remaining amenity, neighbouring openings, boundaries and surveyed trees. We test those site conditions before setting a footprint or selecting the planning route.
Single- and two-storey additions raise different questions. A second storey can engage first-floor outlook, privacy, daylight and enclosure, with the result depending on the measured plot and neighbour relationship rather than a local rule of thumb. We compare the options before committing to an application design.
A side extension can widen a kitchen or dining room where the measured side space, ownership and building form allow it. Check the boundary, rights of way, drainage and the role of the gap in the applicable mapped townscape record. Test permitted development only for a qualifying dwellinghouse against every live restriction; otherwise prepare the application required by the confirmed authority.
Roof form and materials are where a rear or side extension is won or lost aesthetically. A flat roof with a discreet parapet, a shallow mono-pitch or a glazed lantern each suit different host buildings, and the right choice depends on the eaves height, the pattern of the existing rear elevation and how the extension is seen from the garden. Where the villa is stucco-fronted we consider whether render, London stock brick or a deliberately contemporary material best sits against it, and we detail the junction with the original wall so the addition reads as subordinate.
Daylight, sunlight and right to light need separate consideration where the measured proposal could affect neighbouring openings. The responsible authority decides what planning evidence is proportionate; a right-to-light assessment is a separate civil exercise that planning permission does not resolve. Sections can test height and boundary relationships without predicting either outcome.
From there the route is coordinated. We survey the house, confirm the authority and mapped constraints, test the extension against planning and daylight evidence, and prepare the applicable consent and Building Regulations drawings. If the measured design is notifiable under the Party Wall etc. Act 1996, that separate procedure can be programmed with the relevant owners without presuming that it applies.
Local analysis
Rear projection must be tested against the measured garden, adjoining openings, boundaries and the applicable planning and heritage context. A detached-house precedent cannot establish the result for a semi-detached pair or another site. We model the proposal in section so the footprint is based on site evidence rather than a Westminster-only assumption.
Where the applicable appraisal identifies gaps or landscaped settings as significant, a side or flank extension should explain its effect on that specific townscape. We assess whether the measured side space is private and enclosed or visible as part of the street, while keeping ownership, drainage and neighbour questions separate from the conservation assessment.
Materials and roof form should follow the surveyed host building and the applicable planning context. We compare matching and contrasting approaches, resolve the junction with the original wall and show how the addition relates to the eaves and elevation. Those design choices support an evidence-based submission but do not secure Westminster or Camden approval.
Thinking about a project in St John's Wood?
Send the address and a short description. We will confirm the likely approval route and the drawings your project needs.
Local planning
Confirm the complete address and application site before selecting Westminster or Camden policy, validation requirements, planning history and the mapped conservation record. A neighbouring permission or street description cannot allocate the authority or designation for this house.
For a qualifying dwellinghouse, test the proposed rear or side work against every relevant Part 1 limitation, condition, planning-history restriction and live Article 4 direction. Conservation-area status adds class-specific limits but does not remove every householder right; flats do not use Part 1. If an application is required, the statutory non-major target runs from validation and is not an end-to-end promise.
Party Wall procedures are separate from planning and apply only where the actual work is notifiable, such as defined line-of-junction or party-structure work, or excavation meeting the Act's foundation and geometry tests. Establish the boundaries, neighbour foundations and structural design before deciding whether notice is required.
Westminster and Camden maintain separate St John's Wood conservation records. If the complete site is inside a mapped conservation area, use that council's current map and applicable appraisal to assess the extension's roof form, height, materials, garden setting and trees; do not infer designation from the place-name or postcode.
Check the exact address on the relevant council map for any locally identified building and read that record separately from the National Heritage List. Where a local heritage record applies, use its identified significance when designing the addition.
Search the exact address on the National Heritage List and the correct council records. Listed-building consent is required where demolition, alteration or extension affects a listed building's special architectural or historic interest; planning permission and listed-building consent remain separate decisions.
For the wider local-authority picture — policies, timescales and application routes — see planning in Westminster.
Services
Extensions & Renovations
Planning & Consents
Technical & Building Regulations
Leasehold & Licence to Alter
Nearby
Send us the complete St John's Wood address, application site and a description of the proposed extension. We will identify whether Westminster or Camden applies, check mapped heritage and neighbour questions, and set out the proportionate design and drawing route without promising approval.
