Camden's most space-efficient loft solution when PD-route dormers are blocked. Our chartered team designs mansards that get approved in Camden conservation areas — with heritage statements and planning officer negotiation built in.
For Camden homeowners in Victorian and Edwardian terraces, a mansard roof extensions package is the full measured-survey-to-submission drawing set London Borough of Camden needs in order to determine an application: existing and proposed plans, elevations and sections at 1:100 and 1:50, a location and site plan, and the supporting statements the case officer asks for.
Prepared and reviewed by the chartered technologist team at Architectural Drawings London — MCIAT chartered, £2m PI insured.Last reviewed 2026-08-03.
Camden's most space-efficient loft solution when PD-route dormers are blocked. Our chartered team designs mansards that get approved in Camden conservation areas — with heritage statements and planning officer negotiation built in.
Housing stock in Camden: Victorian and Edwardian terraces, Georgian townhouses in Bloomsbury and Hampstead, post-war mansion blocks, modern developments in King's Cross.
Character: Creative, affluent in Hampstead and Primrose Hill; dense mixed-use around Camden Town and Kings Cross; academic character in Bloomsbury.
Article 4: Article 4 removes permitted development for HMO conversions (C3 to C4) across the borough, plus restrictions on basement extensions in 12 conservation areas.
Basement policy: Camden's basement policy (Policy A5) restricts single-storey basements to 50% of garden area; double-storey basements generally refused outside commercial zones.
We check against Camden Council's mansard design guide and design to match the terrace.
Required for Camden's conservation areas — demonstrates the mansard respects character and townscape.
Accurate photomontage showing how the mansard sits alongside neighbours — often decisive at Camden Council committee.
Mansards invariably trigger Party Wall notices in Camden's dense terraced streets. Structural package includes new ridge, tie beams, floor joists.
Full liaison with Camden Council planning officer, committee representation if called in.
Part L thermal, Part B fire (critical on mansards), Part E acoustic separation.
Single planning or regs submission.
Planning + building regs + structural.
Listed, conservation, complex sites.
Move the controls for an indicative figure. It anchors your budget — it is not a quote. Every project is priced after a free survey.
Build costs are separate and quoted by your contractor. See our published fees.
Every Camden postcode district we draw in, the stock that dominates it and the authority that validates a mansard roof extension there. Camden fees below are the statutory England rates for 2026, not mansard roof extension estimates.
| Postcode | Area | Dominant stock | What it means for a mansard roof extension |
|---|---|---|---|
| EC1N | Hatton Garden | Victorian and Edwardian terraces | Hatton Garden sits wholly inside EC1N, so Camden Council validates every mansard roof extension submitted from an EC1N address. |
| N19 | Archway / Tufnell Park | Victorian terraces, post-war flats | N19 straddles a boundary: Archway / Tufnell Park addresses fall to Islington Council or Camden Council, so confirm which authority validates the mansard roof extension before submitting N19 drawings. |
| NW2 | Cricklewood / Neasden | Edwardian villas and terraces | A mansard roof extension in Cricklewood / Neasden may land with Brent Council or Barnet Council or Camden Council — NW2 crosses the boundary, and the NW2 policies map decides it street by street. |
| NW8 | St John's Wood | Victorian villas, mansion blocks | NW8 straddles a boundary: St John's Wood addresses fall to Westminster City Council or Camden Council, so confirm which authority validates the mansard roof extension before submitting NW8 drawings. |
| WC2B | Covent Garden / Holborn | Victorian and Edwardian terraces | WC2B straddles a boundary: Covent Garden / Holborn addresses fall to Westminster City Council or Camden Council, so confirm which authority validates the mansard roof extension before submitting WC2B drawings. |
| N1C | King's Cross | Modern apartments, converted warehouses | A mansard roof extension at an N1C address in King's Cross is determined by Camden Council under its own Local Plan policies for King's Cross. |
| N6 | Highgate | Georgian villas, Victorian and Edwardian semis | N6 straddles a boundary: Highgate addresses fall to Camden Council or Haringey Council, so confirm which authority validates the mansard roof extension before submitting N6 drawings. |
| NW1 | Camden Town / Regent's Park | Victorian terraces, mansion blocks | Camden Town / Regent's Park is split at NW1. Either Camden Council or Westminster City Council can determine a mansard roof extension here, so the NW1 address is checked against both policies maps first. |
Roof pitch, wall build-up and plot depth change every few Camden streets, and each one changes what a mansard roof extension can achieve at that address.
How designation changes a Camden mansard roof extension: Camden Council maintains 40 conservation areas, including Camden Town, Fitzrovia, Hampstead. Inside any of them a Camden mansard roof extension cannot rely on permitted development, and the route becomes a £548 householder application determined in 8 weeks rather than a £249 prior approval in 6 weeks. Primrose Hill sets the tone for Camden casework.
Article 4 and your Camden mansard roof extension: Article 4 removes permitted development for HMO conversions (C3 to C4) across the borough, plus restrictions on basement extensions in 12 conservation areas. At a N1C address that matters twice over, because Camden Council applies the direction unevenly across Camden — we read the Camden policies map for the exact N1C address before quoting mansard roof extensions.
Digging below a Camden property: Camden's basement policy (Policy A5) restricts single-storey basements to 50% of garden area; double-storey basements generally refused outside commercial zones. Where a mansard roof extension in Camden involves excavation that is read beside the Party Wall etc. Act 1996, which needs two months notice for a Camden dig within 3 m of a neighbour, and Camden Council expects the N1C ground conditions addressed in the application.
Camden housing stock: Victorian and Edwardian terraces, Georgian townhouses in Bloomsbury and Hampstead, post-war mansion blocks, modern developments in King's Cross. Creative, affluent in Hampstead and Primrose Hill; dense mixed-use around Camden Town and Kings Cross; academic character in Bloomsbury. Read that before choosing a mansard roof extension route in Camden — construction, not postcode, sets what is achievable. Camden Council charges £548 for a householder application and has 8 weeks to determine it.
Sources for this Camden mansard roof extension page: borough policies maps and conservation-area registers (2025–26), Royal Mail postcode district boundaries, the Town and Country Planning (Fees for Applications) (England) Regulations, the Town and Country Planning (General Permitted Development) (England) Order 2015 as amended, and the Party Wall etc. Act 1996.
Of 76 listed building and conservation area consent appeals decided in Camden over the window covering appeals decided 2016-2026, Camden was upheld more often than most London councils — only 22.4% of appeals succeeded, against 28.5% across London. 17 were allowed and 56 dismissed, with 3 split. Mansards concentrate on terraces in conservation areas and on listed buildings, where consent runs separately from planning permission. These 76 Camden consent appeals are the contested minority.
Half of those Camden appeals took more than 113 days to decide from the day the appeal started — time added on top of the council's own determination period, which is the argument for getting the application right first. 14.5% of them (11 cases) involved a conservation area, so heritage argument carries real weight in Camden. 18.4% affected the setting of a listed building. 89.5% were decided by written representations rather than a hearing or inquiry, meaning the written case and the drawings were the whole of the evidence.
76 listed building and conservation area consent appeals decided in Camden. Source: Planning Inspectorate casework, OGL v3.0.
Direct answers to the questions Camden homeowners ask every week about mansard roof extensions.
Start a free quote →Mansards in Camden are more heavily scrutinised than in outer boroughs. Camden Council prioritises heritage and townscape — approvals require exceptional design quality, clear precedents on the street, and a full Heritage Statement. We've delivered mansard approvals in the borough; each application is bespoke.
A 70° front slope is typical for Camden mansards — steep enough to maximise floor area while reading as a roof rather than a full additional storey. Front dormers should be small and symmetrical. Camden Council's design guide (where published) takes precedence on detail.
Often yes, but Camden Council favours applications supported by wider street precedents. Where mansards already exist nearby in Camden, approval is far more likely. We review street precedents at the feasibility stage.
A Camden mansard carries more design work than a dormer — heritage statement, street-elevation massing and conservation-led detailing on top of planning, building regulations and structural calculations. Build cost then varies with size, roof geometry and site access. Our design fee is fixed before we start; see our fees.
Full-height — typically 2.3–2.5m ceiling from the new floor. Unlike a dormer, which gives partial head height, a mansard provides a complete additional storey within Camden's victorian and Edwardian terraces terraced context.
We cover all Camden postcodes — NW1, NW3, NW5, NW6, WC1, WC1H, WC1N, WC1R, WC1V, WC1X, N6, N7, N19 — and have submitted mansard applications across the borough. Our heritage statement and design-and-access statement are included in every mansard package.
Camden's victorian and Edwardian terraces terraced stock is the natural context for mansard extensions — they were originally designed for Victorian and Edwardian rows. Feasibility depends on street precedent, conservation area status and party wall implications. We assess all three at the free site visit.
A mansard adds a full upper storey — typically 35–45m² of usable floor space. In Camden this often converts a 3-bed house to 4 or 5 beds. The steep front slope (70°) and flat top read as a roof, not a full floor, which is why Camden Council accepts them more readily than a simple box extension.
If your property sits on a boundary, here are the neighbouring options.
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