Rear extension in Camden
Do you need planning permission for a rear extension in Camden?
Often yes, but it depends on exactly what you're proposing, not just your postcode. Camden's conservation areas remove side extensions and any two-storey rear addition from permitted development outright, but a single-storey rear extension within the standard 3m (attached) or 4m (detached) limits can still qualify — Camden's own Article 4 directions in streets around Hampstead and Belsize target front-and-side changes like windows and boundary treatments, not the rear allowance. Flats have no permitted development rights at all, so confirm the exact address before assuming either way.
Precedent-driven: hold to your street's established projection depth and match the stock brick.
Camden's terraced stock varies street by street — Bloomsbury's Georgian runs, the Victorian terraces around Kentish Town and Camden Town, the larger villas nearer Belsize Park and Hampstead — so there's no single 'established depth' that applies across the borough. Officers are comparing your proposal against what's already been consented on your specific row, which makes your own street's planning history more useful than any general rule of thumb. It's also why Camden's case officers respond well to applications that arrive with a daylight assessment and a matched-materials specification already attached, rather than produced after they ask.
What actually applies in Camden
Conservation areas in Camden
Real · planning.data.gov.ukEvery designated conservation area in Camden from the official dataset — inside one, permitted development narrows and design scrutiny rises.
- Alexandra Road
- Bartholomew Estate
- Belsize
- Bloomsbury
- Camden Broadway
- Camden Square
- Camden Town
- Charlotte Street
- Dartmouth Park
- Denmark Street
- Elsworthy
- Eton
- Fitzjohns Netherhall
- Fitzroy Square
- Hampstead
- Hanway Street
- Harmood Street
- Hatton Garden
- Highgate Village
- Holly Lodge Estate
- Inkerman
- Jeffrey's Street
- Kelly Street
- Kentish Town
- Kings Cross St Pancras
- Kingsway
- Mansfield
- Parkhill
- Primrose Hill
- Priory Road
- Redington Frognal
- Regents Canal
- Regents Park
- Rochester
- Seven Dials (Covent Garden)
- South Hampstead
- South Hill Park
- St Johns Wood
- West End Green
- West Kentish Town
Source: planning.data.gov.uk · Open Government Licence. Boundaries are checked at address level by the area report.
Article 4 directions in Camden
Real · planning.data.gov.ukArticle 4 directions in Camden remove specific permitted development rights street by street — the single most common reason a "no permission needed" project turns out to need one.
- 115, 117, 119, 121A, 127-129 Parkway and 1 Park Willage East
- 13-51 (odd) & 16-60 (even) Belsize Avenue
- 147 Kentish Town Road
- 187 Kentish Town Road
- 32-66 (even) & 72-90 (even) South Hill Park, NW3 (South Hill Park Estate Conservation Area)
- 33 York Rise, NW5 (Dartmouth Park Conservation Area)
- 67 Fitzjohns Avenue area
- Basements
- Belsize Conservation Area (various properties)
- Belsize Conservation Area Non-immediate Article 4
- Commercial, Business, and Service (Use Class E) to residential (Use Class C3) (in CAZ)
- Commercial, Business, and Service (Use Class E) to residential (Use Class C3) (outside CAZ)
- Fitzjohns/Netherhall Conservation Area Non-immediate Article 4
- Frognal Way
- Hampstead Conservation Area (excl. Frognal Way) (various properties)
- Hampstead Conservation Area (excl. Frognal Way) Non-immediate Article 4
- Launderettes to dwelling houses (Sui Generis to C3)
- Primrose Hill Conservation Area (various properties) - UNDER REVIEW
- Redington/Frognal Conservation Area Non-immediate Article 4
- South Hampstead Conservation Area Non-immediate Article 4
- Swiss Cottage Conservation Area (various properties)
Source: planning.data.gov.uk · Open Government Licence. Boundaries are 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 Camden, 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 Camden?
| 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 Camden
The 45-degree daylight test does real work on Camden's tighter Victorian plots, trimming depth before a design ever reaches committee. Conservation-area material conditions — brick match, mortar type, roof finish — are the detail that surfaces after pricing rather than before, so get them confirmed at design stage, not after a contractor has quoted.
Camden planning, area by area
Almost certainly yes — assume a full householder application.
Do I need permission? →Usually a full application — and the roof form decides it.
Do I need permission? →Yes — assume a full planning application, and expect Camden's strict basement policy.
Do I need permission? →If your Hampstead property is listed — and a high proportion of the village's Georgian and early-Victorian houses are — then listed building consent is needed for any works that affect its special character, inside and out, separately from and on top of planning permission.
Do I need permission? →Usually a full householder application — and your tenure is the first question.
Do I need permission? →Usually a full application — and often not available at all if you're in a converted flat.
Do I need permission? →Yes — a full planning application, under Camden's strict basement policy.
Do I need permission? →Some of Belsize Park's grand villas are listed, and if yours is, listed building consent is needed for works affecting its character inside and out — separate from and additional to planning permission.
Do I need permission? →Usually a full householder application, and the constraint is as much the neighbours as the conservation area.
Do I need permission? →Usually a full application — permitted-development loft rights are removed in the conservation area and the Article 4 directions reinforce it.
Do I need permission? →Yes — a full planning application under Camden's strict basement policy, and the tight terraces make the party-wall and neighbour dimension acute.
Do I need permission? →A number of Primrose Hill's terraces are listed, and if yours is, listed building consent is required for works affecting its character inside and out — additional to planning permission.
Do I need permission? →Postcode districts in Camden
NW1 runs from the Nash terraces around Regent's Park through Camden Town to Somers Town.
NW1 — Camden Town, Primrose Hill & Regent's Park →NW3 is one of the most constrained districts in London: most of Hampstead village, Belsize Park and the Fitzjohns/Netherhall area falls within conservation areas, with Article 4 directions stripping permitted development from many streets.
NW3 — Hampstead & Belsize Park →NW5's flat-fronted Victorian terraces are classic side-return and loft territory.
NW5 — Kentish Town, Dartmouth Park & Tufnell Park →NW6 straddles Camden and Brent, with West Hampstead's mansion blocks and Victorian terraces on the Camden side.
NW6 — West Hampstead & Kilburn →WC1 is Georgian Bloomsbury: garden squares, listed terraces and institutional ownership.
WC1 — Bloomsbury & King's Cross →EC1N is Hatton Garden and the streets around Leather Lane: narrow historic plots, jewellery workshops and showrooms at street level, and later commercial infill running down to the Camden/City of London boundary.
EC1N — Hatton Garden →N1C is King's Cross Central — the old railway lands behind King's Cross and St Pancras, rebuilt as a masterplanned quarter of new apartment blocks, converted gasholders and repurposed goods buildings around Granary Square and the canal.
N1C — King's Cross Central →W1T is eastern Fitzrovia: Georgian terraces above shops around Charlotte Street and Goodge Street, later blocks of flats, and a thick layer of post-war and media-industry offices.
W1T — Fitzrovia →WC1A is the commercial seam where Bloomsbury meets Holborn — New Oxford Street, Bloomsbury Way and Museum Street, where shops, offices and university buildings hold the ground floors and the residents live in flats above them or in side-street mansion blocks.
WC1A — New Oxford Street & Holborn →WC1B is Bloomsbury at its most intact: Georgian terraces around Bedford Square and Great Russell Street, garden squares in institutional and estate ownership, and the British Museum anchoring the middle of it.
WC1B — Bloomsbury & the British Museum →WC1E is the university quarter — Gower Street, Store Street and Torrington Place, where UCL and its faculty buildings sit among long runs of brown-brick Georgian terrace.
WC1E — Bloomsbury & Gower Street →WC1H covers northern Bloomsbury towards Euston and King's Cross — the Gordon and Tavistock Square terraces, the crescent at Cartwright Gardens, Judd Street, and the post-war blocks and student halls filling the gaps.
WC1H — Bloomsbury & Euston →WC1N is eastern Bloomsbury — Queen Square, Great Ormond Street, Guilford Street and Lamb's Conduit Street — where hospitals and Georgian terraces share the same blocks.
WC1N — Queen Square & Great Ormond Street →WC1R is legal London: the gardens and chambers of Gray's Inn, the wide Georgian frontages of Bedford Row and Jockey's Fields, and the streets around Red Lion Square.
WC1R — Gray's Inn & Bedford Row →WC1V is largely commercial — the office frontages of High Holborn and the blocks around Procter Street, running down towards the City boundary — with a small residential population in flats above and behind the main street.
WC1V — High Holborn →WC1X is the most residential slice of WC1 — Georgian terraces and squares off Gray's Inn Road, the Calthorpe and Lloyd Baker streets climbing towards Clerkenwell, mansion blocks, and Mount Pleasant on the eastern side.
WC1X — Mount Pleasant & King's Cross Road →WC2A is the legal quarter: Lincoln's Inn and Lincoln's Inn Fields, barristers' chambers, the Royal Courts of Justice, Chancery Lane and the LSE campus, with the district's edges reaching Westminster, Islington and the City.
WC2A — Holborn & Lincoln's Inn →WC2B is the Kingsway–Aldwych spine and the streets behind it — Drury Lane, Great Queen Street and Freemasons' Hall, on the northern fringe of Covent Garden.
WC2B — Covent Garden & Kingsway →WC2H runs from Seven Dials and Denmark Street across Cambridge Circus to Charing Cross Road and Leicester Square, with the Westminster boundary close by.
WC2H — Seven Dials & Covent Garden →Rear extension in Camden, asked straight
How much does a rear extension cost in Camden?
Does a Camden conservation area automatically rule out permitted development for a rear extension?
What projection depth will Camden planners accept?
How long does a rear extension application take in Camden?
Do I need a party wall agreement for a Camden rear extension?
What applies at your address?
Borough-level rules only narrow it down. Enter a Camden 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 Camden
A rear extension is a design-and-consent job first: someone has to draw it and take it through Camden'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.