Rear extension in Southwark
Do you need planning permission for a rear extension in Southwark?
Often not, outside the conservation areas — much of Southwark's terrace stock keeps permitted development rights for a single-storey rear extension within the size limits, or larger via prior approval. Inside a conservation area a full application is the norm, with roof form and materials deciding outcomes under the council's Residential Design Standards SPD. Flats have no permitted development rights.
Camberwell, Peckham and Dulwich terraces extend constantly; outside the conservation areas PD or prior approval often carries it.
Southwark really is two planning worlds: the dense, often listed riverside from Bankside and Borough through Bermondsey, and the inland Victorian and Georgian terrace belts of Camberwell, Peckham, Dulwich and East Dulwich where rear extensions are everyday projects. Most of the borough's many Article 4 directions protect pubs, shopping frontages and commercial-to-residential conversion rather than householder extensions — so for homeowners, conservation-area designation and listed status are what actually narrow the rear-extension route. Match your scheme to established depth and materials on your own street.
What actually applies in Southwark
Conservation areas in Southwark
Real · planning.data.gov.ukEvery designated conservation area in Southwark from the official dataset — inside one, permitted development narrows and design scrutiny rises.
- Addington Square
- Bear Gardens
- Bermondsey Street
- Borough High Street
- Camberwell Green
- Camberwell Grove
- Camberwell New Road
- Caroline Gardens
- Cobourg Road
- Dulwich Village
- Dulwich Wood
- Edward III's Rotherhithe
- Elliot's Row
- Glengall Road
- Grosvenor Park
- Holly Grove
- Honor Oak Rise
- Kennington Park Road
- Kentish Drovers and Bird in Bush
- King's Bench
- Larcom Street
- Liberty of the Mint
- Liverpool Grove
- Livesey
- Nunhead Cemetry
- Nunhead Green
- Old Barge House Alley
- Pages Walk
- Peckham Hill Street
- Pullens Estate
- Rye Lane Peckham
- Sceaux Gardens
- St Georges Circus
- St Marys Rotherhithe
- St Saviours Dock
- Stradella Road
- Sunray Estate
- Sutherland Square
- The Gardens
- The Mission
- Thomas A'Becket and High Street
- Thorburn Square
- Thrale Street
- Tooley Street
- Tower Bridge
- Trafalgar Avenue
- Trinity Church Square
- Union Street
- Valentine Place
- Walworth Road
- West Square
- Wilson Grove
- Yates Estate and Victory
…plus 2 further designated areas.
Source: planning.data.gov.uk · Open Government Licence. Boundaries are checked at address level by the area report.
Article 4 directions in Southwark
Real · planning.data.gov.ukSouthwark records hundreds of Article 4 directions, but they overwhelmingly protect public houses (from demolition, alteration or change of use), protected shopping frontages, and commercial-to-residential conversions and site allocations — not householder permitted development. For homeowners, conservation-area designation and listed status are what narrow extension rights; check the area report for what applies at a specific address.
Source: planning.data.gov.uk · Open Government Licence · 371 directions recorded. Checked at address level by the area report.
Prices: HM Land Registry UK House Price Index, December 2025 · 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 Southwark, 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 Southwark?
| 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 Southwark
Do not assume Southwark's large Article 4 count means your house extension is restricted — most of those directions are not about householder permitted development. The real traps are conservation designation, listed status on the riverside stock, the 45-degree daylight test on tight plots, and flats with no permitted development at all.
Postcode districts in Southwark
SE1 is Southwark's listed riverside — the Borough High Street, Bermondsey Street, Tower Bridge and Trinity Church Square conservation areas, much of it statutory-listed.
SE1 — Borough, Bankside & Bermondsey →SE5 is Camberwell's Georgian and Victorian stock — the Camberwell Grove, Camberwell Green, Addington Square and Sceaux Gardens conservation areas.
SE5 — Camberwell →SE15 runs from Rye Lane Peckham to the Nunhead Cemetery and Holly Grove conservation areas.
SE15 — Peckham & Nunhead →SE16 covers the St Marys and Edward III's Rotherhithe conservation areas, the Surrey Quays redevelopment and the Wilson Grove cottages.
SE16 — Rotherhithe & Surrey Quays →SE22 reaches the Dulwich Village, Sunray Estate and Stradella Road conservation areas, where the Dulwich Estate's private scheme of management adds a layer of control alongside planning.
SE22 — East Dulwich & Dulwich Village →SE17 is Walworth and the Kennington edge in Southwark — dense terraces and a high share of flats.
SE17 — Walworth & Kennington edge →SE21 covers Dulwich Village and West Dulwich in Southwark (with a Lambeth edge).
SE21 — Dulwich Village & West Dulwich →Rear extension in Southwark, asked straight
Do Southwark's Article 4 directions stop my rear extension?
How much does a rear extension cost in Southwark?
Can I extend under permitted development in Camberwell, Peckham or Dulwich?
What about a flat in Southwark?
Do I need a party wall agreement?
What applies at your address?
Borough-level rules only narrow it down. Enter a Southwark postcode for the live constraint check — conservation area, Article 4 and sold-price comparables, cited to source.
Need it in writing for one address? A planning permission report for a Southwark property — from £59, or surveyor-reviewed from £295.
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.