Rear extension in Wandsworth
Do you need planning permission for a rear extension in Wandsworth?
Often yes without an application — Wandsworth's Victorian terraces largely retain the standard permitted development rights for single-storey rear extensions: up to 3m on attached houses, 4m on detached, or 6m/8m via the larger-home-extension prior approval route outside conservation areas. Inside one of the borough's conservation areas the single-storey rear allowance usually survives too, though two-storey and side extensions do not. Because the national Article 4 dataset holds no geometry for Wandsworth, check the council's own register before assuming those rights are intact at your specific address.
The 'between the commons' terraces extend routinely; scale against the neighbour's daylight to clear the 45-degree test.
Rear extensions are the default move on Wandsworth's dense Victorian terrace belt, from the streets between the commons to the villa stock nearer Putney and Battersea, and the borough has one of London's deepest precedent records for the project. That volume cuts both ways: officers know exactly what a consented extension on your street looks like, so a scheme that matches the established depth and brickwork tends to move quickly, while one that pushes past it invites direct comparison with what's already been refused nearby.
What actually applies in Wandsworth
Conservation areas in Wandsworth
Real · planning.data.gov.ukEvery designated conservation area in Wandsworth from the official dataset — inside one, permitted development narrows and design scrutiny rises.
- Alton
- Bathgate Road
- Battersea Park
- Battersea Square
- Charlwood Road and Lifford Street
- Clapham Common
- Clapham Junction
- Coalecroft Road
- Culverden Road
- Deodar Road
- Dinsmore Road
- Dover House Estate
- East Putney
- Garrad's Road
- Heaver Estate
- Landford Road
- Latchmere Estate
- Magdalen Park
- Mellison Road
- Nightingale Lane
- Old Devonshire Road
- Oxford Road
- Park Town
- Parkfields
- Putney Embankment
- Putney Heath
- Putney Lower Common
- Roehampton Village
- Rusholme Road
- Shaftesbury Park Estate
- St John's Hill Grove
- Streatham Park
- Sutherland Grove
- Three Sisters
- Totterdown Fields
- Town Hall Road
- Victoria Drive
- Wandsworth Common
- Wandsworth Town
- West Hill Road
- West Putney
- Westbridge Road
- Westmead
- Wimbledon North
- Wimbledon Park Road
Source: planning.data.gov.uk · Open Government Licence. Boundaries are checked at address level by the area report.
Article 4 directions in Wandsworth
Real · planning.data.gov.ukNo Article 4 geometry for Wandsworth appears in the national planning.data.gov.uk dataset. The borough's most significant householder control is its basement regime — Local Plan Policy LP6 (Basements and Subterranean Developments) and the council's basement guidance: multi-level basements are not supported, roughly half of front and back gardens should be retained, and at least a metre of soil above the basement is expected. Check the council's planning pages for any Article 4 directions in force.
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 Wandsworth, 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 Wandsworth?
| 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 Wandsworth
The recurring trip point on Wandsworth's terraced plots is the 45-degree daylight test, which can trim a scheme's depth below what a neighbouring extension already achieved. Inside a conservation area, brick and roofline matching gets checked closely and is worth pricing before you commit to a design — and because the borough's Article 4 position isn't confirmed in the national dataset, don't assume permitted development rights are intact without checking the council's register first.
Postcode districts in Wandsworth
SW18 covers the Wandsworth Town, Magdalen Park and Old Devonshire Road conservation areas and the Victorian 'Tonsleys'.
SW18 — Wandsworth Town & Earlsfield →SW11 includes the Battersea Park, Battersea Square, Shaftesbury Park Estate and Heaver Estate conservation areas around Clapham Junction — the 'between the commons' terrace market.
SW11 — Battersea & Clapham Junction →SW12 is Balham — the streets around Nightingale Lane and the Clapham Common conservation-area edge, classic family-terrace stock.
SW12 — Balham →SW15 runs from the Putney Embankment and Putney Heath conservation areas to the Dover House Estate and Roehampton Village.
SW15 — Putney & Roehampton →SW17 is Tooting — the Totterdown Fields conservation area, an early London County Council cottage estate, and the long terraces around the commons.
SW17 — Tooting →Rear extension in Wandsworth, asked straight
How deep can I extend under permitted development in Wandsworth?
Does Wandsworth have an Article 4 direction affecting rear extensions?
What gets a Wandsworth rear extension refused?
How much does a rear extension cost in Wandsworth?
Can I extend if my Wandsworth home is a flat?
What applies at your address?
Borough-level rules only narrow it down. Enter a Wandsworth 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 Wandsworth
A rear extension is a design-and-consent job first: someone has to draw it and take it through Wandsworth'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.