Rear extension in Greenwich
Do you need planning permission for a rear extension in Greenwich?
Outside the conservation areas, much of the Victorian and interwar stock in Charlton, Eltham and Plumstead keeps permitted development rights for a single-storey rear extension within the limits, or larger via prior approval, to the Residential Extensions, Basements and Conversions SPD. Inside a conservation area — or where a householder Article 4 applies — expect a full application. Listed buildings in the historic core need listed building consent as well.
Charlton, Eltham and Plumstead terraces extend under PD; the Greenwich, Blackheath and Westcombe Park conservation areas need a full application.
The Royal Borough holds a major heritage core around Maritime Greenwich and a string of conservation areas, with listed buildings common in the historic town. Beyond those protected pockets, ordinary terrace and suburban stock still supports everyday rear extensions. The SPD sets design expectations in and out of conservation areas; riverside and park settings can add landscape scrutiny on prominent plots.
What actually applies in Greenwich
Conservation areas in Greenwich
Real · planning.data.gov.uk14 designated areas are recorded in the official dataset for this borough without published names. The area report still checks an address against their real boundaries — see the council's own conservation-area and Article 4 pages for the named schedules.
Source: planning.data.gov.uk · Open Government Licence · 14 recorded.
Article 4 directions in Greenwich
Real · planning.data.gov.ukNo Article 4 geometry for Greenwich appears in the national planning.data.gov.uk dataset, but the Royal Borough operates householder Article 4 directions in a number of its conservation areas — among them the Ashburnham Triangle, West Greenwich, East Greenwich, the Rectory Field, the Shrewsbury Park Estate and the Progress Estate — removing permitted development rights so that visible external alterations need planning permission. The Residential Extensions, Basements and Conversions Guidance SPD sets the design rules. Check the council's Article 4 pages for the position at a specific address.
Source: planning.data.gov.uk · Open Government Licence. Checked at address level by the area report.
Prices: HM Land Registry UK House Price Index, January 2026 · Open Government Licence.
The planning route — PD or permission?
Permitted development (GPDO Class A) covers single-storey rear extensions up to 3m beyond the original rear wall on attached houses and 4m on detached, with a maximum height of 4m. The 'larger home extension' route extends this to 6m/8m through prior approval with neighbour consultation — but that larger route is not available in conservation areas.
In conservation areas, the basic 3m/4m single-storey rear PD allowance usually survives — what conservation-area status removes is side extensions and two-storey rear extensions. An Article 4 direction can remove more, but Camden's directions in Hampstead and Belsize target front-and-side appearance (solar panels, window changes, boundary treatments), not the single-storey rear allowance. Flats have no PD rights at all. Two-storey rear extensions in conservation areas always need full permission.
Practical rule across London: check the address first. If a conservation area or Article 4 direction applies, budget for a full householder application decided on design, neighbour daylight (the 45-degree test) and materials.
Permitted development limits — rear extension
| Single-storey rear depth — attached house | 3m beyond the original rear wall |
| Single-storey rear depth — detached house | 4m beyond the original rear wall |
| Larger extension via prior approval | 6m attached / 8m detached — not in conservation areas |
| Maximum height (single storey) | 4m |
| Two-storey rear in a conservation area | Full planning permission required |
| Flats | No permitted development rights |
Limits summarise the General Permitted Development Order (Schedule 2, Part 1) as it applies in London. In Greenwich, a conservation area, Article 4 direction or listed status changes the route — the panels above show what is designated, and the address check confirms what applies at your property.
How much does a rear extension cost in Greenwich?
| Cost per m² (low — straightforward site) | £3,000 |
| Cost per m² (expected) | £3,800 |
| Cost per m² (high — conservation spec, hard access) | £4,600+ |
| Typical build cost (12–18m² single storey) | £36,000 – £83,000 |
| Professional fees, surveys, party wall (add) | 10–18% of build |
Indicative London ranges calibrated from real project data. Conservation-area specifications (matching stock brick, lime mortar, bespoke glazing) and restricted rear access are the two biggest cost drivers. VAT not included.
Realistic timeline
| Design and drawings | 4–8 weeks |
| Planning decision (full application) | 8–12 weeks (8-week statutory target) |
| Prior approval route, where available | 42 days |
| Party wall agreements | 4–10 weeks (parallel) |
| Build | 3–5 months |
What catches people out in Greenwich
Starting design before checking conservation, Article 4 and listing status is the classic false start near the heritage core. National geometry does not currently hold the borough's Article 4 directions — confirm those on the council's pages as well.
Postcode districts in Greenwich
SE10 is the Maritime Greenwich World Heritage core — the Old Royal Naval College, Queen's House and Royal Observatory — wrapped by the West Greenwich, East Greenwich and Ashburnham Triangle conservation areas, several with Article 4 directions.
SE10 — Greenwich & Maritime Greenwich →SE3 covers the Blackheath and Westcombe Park conservation areas around the heath (Blackheath is shared with Lewisham).
SE3 — Blackheath & Westcombe Park →SE7 is Charlton — the Charlton Village conservation area around Charlton House and the Rectory Field, which carries an Article 4 direction.
SE7 — Charlton →SE9 is Eltham — home to the Progress Estate, a celebrated First World War garden suburb with an Article 4 direction, and Eltham Palace nearby.
SE9 — Eltham →SE18 covers Woolwich, the Royal Arsenal riverside and the Shrewsbury Park Estate conservation area (which carries an Article 4 direction) above Plumstead.
SE18 — Woolwich & Plumstead →SE2 covers Abbey Wood and the Thamesmead fringe, mainly in Greenwich with a Bexley edge.
SE2 — Abbey Wood & Thamesmead fringe →SE28 is Thamesmead — later twentieth-century stock and estate layouts in Greenwich (with a Bexley edge), different from the Victorian terrace belts further west.
SE28 — Thamesmead →Rear extension in Greenwich, asked straight
Do I need planning permission for a rear extension in Greenwich?
How much does a rear extension cost in Greenwich?
Will I need listed building consent?
Why might the free area report miss Article 4s?
Do I need a party wall agreement?
What applies at your address?
Borough-level rules only narrow it down. Enter a Greenwich postcode for the live constraint check — conservation area, Article 4 and sold-price comparables, cited to source.
Free, and it stays free — no account, no payment. The check reads official geometry at the property's own coordinates; listed status, lease terms and the state of the building all sit outside it.
Who to talk to about a rear extension in Greenwich
A rear extension is a design-and-consent job first: someone has to draw it and take it through Greenwich's planning route. The neighbour, condition and party wall side is separate work and a different profession — which is why there are two doors here, not one.
An extension is a design and consent job: the scheme, the planning application or prior approval, then the building-regs package.
- Residential design for extensions, lofts, basements and conversions
- Planning applications, pre-application advice and appeals
- Lawful development certificates
- Building-regulations and technical design drawings
- Conservation-area design and listed building consent applications
Excavating foundations within 3m of a neighbour is notifiable — the surveyor serves the party wall notices.
- Building surveys, RICS home surveys and defect diagnosis
- Party wall matters and awards
- Technical due diligence before a purchase
- Leasehold and major-works advisory (Section 20)
- Dilapidations and building pathology
Both practices are independent and separately regulated — Hampstead Chartered Surveyors & Building Consultancy is an RICS-regulated firm (Firm Reg. 923064); Hampstead Architecture and Planning are ARB-registered architects. We publish no fees for their work: each quotes directly for the job in front of them. Your enquiry goes to the practice you choose — we never pass your details to builders or other third parties.
Planning terms on this page
Conservation Area · Article 4 Direction · Permitted development · Full planning · Prior approval · Party wall · Designated land
Plain-English definitions · full planning glossary →
Planning Permission Checker provides planning and cost intelligence for early feasibility only. It is not legal, planning, valuation, architectural, structural, or surveying advice. All estimates are indicative and must be verified by qualified professionals before purchase, design, planning submission, or construction.
Cost estimates are indicative only — not a quotation. Final price depends on survey, specification, structure, access, party wall matters, VAT, professional fees, and contractor availability.
Planning outcomes are not guaranteed. Local planning authorities make final decisions.