Southwark's most space-efficient loft solution when PD-route dormers are blocked. Our chartered team designs mansards that get approved in Southwark conservation areas — with heritage statements and planning officer negotiation built in.
A mansard roof extensions package in Southwark, where the stock is largely Georgian and Regency in Bermondsey and Borough; Victorian terraces in Camberwell and Peckham; Dulwich Estate controlled housing; riverside new-build, is the full measured-survey-to-submission drawing set London Borough of Southwark 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.
Southwark's most space-efficient loft solution when PD-route dormers are blocked. Our chartered team designs mansards that get approved in Southwark conservation areas — with heritage statements and planning officer negotiation built in.
Housing stock in Southwark: Georgian and Regency in Bermondsey and Borough; Victorian terraces in Camberwell and Peckham; Dulwich Estate controlled housing; riverside new-build.
Character: Dulwich Estate private planning scheme affects much of SE21 and SE22; Southwark planning for rest of borough; strong heritage context.
Article 4: Article 4 for HMOs borough-wide; additional Article 4 for office-to-residential in Bermondsey and Elephant & Castle.
We check against Southwark Council's mansard design guide and design to match the terrace.
Required for Southwark's conservation areas — demonstrates the mansard respects character and townscape.
Accurate photomontage showing how the mansard sits alongside neighbours — often decisive at Southwark Council committee.
Mansards invariably trigger Party Wall notices in Southwark's dense terraced streets. Structural package includes new ridge, tie beams, floor joists.
Full liaison with Southwark 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 Southwark postcode district we draw in, the stock that dominates it and the authority that validates a mansard roof extension there. Southwark 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 |
|---|---|---|---|
| SE1 | Bermondsey / Borough / Waterloo | Georgian terraces, post-war flats, new-build | SE1 straddles a boundary: Bermondsey / Borough / Waterloo addresses fall to Southwark Council or Lambeth Council, so confirm which authority validates the mansard roof extension before submitting SE1 drawings. |
| SE5 | Camberwell | Georgian villas, Victorian terraces | Camberwell is split at SE5. Either Southwark Council or Lambeth Council can determine a mansard roof extension here, so the SE5 address is checked against both policies maps first. |
| SE15 | Peckham / Nunhead | Victorian terraces, post-war estates | A mansard roof extension at an SE15 address in Peckham / Nunhead is determined by Southwark Council under its own Local Plan policies for Peckham / Nunhead. |
| SE16 | Bermondsey / Rotherhithe | Warehouse conversions, Georgian terraces, new-build | SE16 covers Bermondsey / Rotherhithe only; Southwark Council handles the mansard roof extension, and Bermondsey / Rotherhithe case officers apply the SE16 conservation-area map. |
| SE17 | Walworth | Post-war estates, new-build towers | SE17 covers Walworth only; Southwark Council handles the mansard roof extension, and Walworth case officers apply the SE17 conservation-area map. |
| SE21 | Dulwich Village | Georgian villas, Edwardian villas (Dulwich Estate) | SE21 straddles a boundary: Dulwich Village addresses fall to Southwark Council or Lambeth Council, so confirm which authority validates the mansard roof extension before submitting SE21 drawings. |
| SE22 | East Dulwich | Victorian and Edwardian terraces | East Dulwich sits wholly inside SE22, so Southwark Council validates every mansard roof extension submitted from an SE22 address. |
| SE24 | Herne Hill | Victorian villas, Edwardian terraces | A mansard roof extension in Herne Hill may land with Lambeth Council or Southwark Council — SE24 crosses the boundary, and the SE24 policies map decides it street by street. |
Roof pitch, wall build-up and plot depth change every few Southwark streets, and each one changes what a mansard roof extension can achieve at that address.
Southwark conservation designations: there are 43 across Southwark Council, Dulwich Village, Peckham Rye, Borough among them. Designation costs a Southwark owner the permitted-development route: a mansard roof extension then needs a £548 householder application over 8 weeks, in place of the £249 prior approval route that takes 6 weeks. Camberwell Grove is the Southwark designation that most often changes a mansard roof extension design.
What Article 4 removes near Southwark: Article 4 for HMOs borough-wide; additional Article 4 for office-to-residential in Bermondsey and Elephant & Castle. Before pricing a mansard roof extension we check whether the SE1 address is inside the mapped area, because Southwark Council draws the Southwark boundary street by street rather than across the whole of Southwark.
What Southwark is built from: Georgian and Regency in Bermondsey and Borough; Victorian terraces in Camberwell and Peckham; Dulwich Estate controlled housing; riverside new-build. Dulwich Estate private planning scheme affects much of SE21 and SE22; Southwark planning for rest of borough; strong heritage context. That mix decides the mansard roof extension route in Southwark more than the postcode does, and it is what a Southwark Council case officer reads first. A householder application costs £548 paid to Southwark Council direct, with 8 weeks to a decision once validated.
Sources for this Southwark 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 33 listed building and conservation area consent appeals decided in Southwark over the window covering appeals decided 2016-2026, Southwark sat close to the London norm, with 27.3% of appeals succeeding against 28.5% city-wide. 9 were allowed and 23 dismissed, with 1 split. Mansards concentrate on terraces in conservation areas and on listed buildings, where consent runs separately from planning permission. These 33 Southwark consent appeals are the contested minority.
Half of those Southwark appeals took more than 99 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. 21.2% of them (7 cases) involved a conservation area, so heritage argument carries real weight in Southwark. 30.3% affected the setting of a listed building. 93.9% were decided by written representations rather than a hearing or inquiry, meaning the written case and the drawings were the whole of the evidence.
33 listed building and conservation area consent appeals decided in Southwark. Source: Planning Inspectorate casework, OGL v3.0.
Direct answers to the questions Southwark homeowners ask every week about mansard roof extensions.
Start a free quote →Very often yes in Southwark. Rear mansards are routinely approved by Southwark Council where the design matches the terrace — including within conservation areas like Camberwell Grove. A Heritage Statement and sensitive design following the borough's published guidance are essential for conservation area mansards.
A 70° front slope is typical for Southwark 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. Southwark Council's design guide (where published) takes precedence on detail.
Often yes, but Southwark Council favours applications supported by wider street precedents. Where mansards already exist nearby in Southwark, approval is far more likely. We review street precedents at the feasibility stage.
A Southwark 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 Southwark's georgian and Regency in Bermondsey and Borough terraced context.
We cover all Southwark postcodes — SE1, SE5, SE15, SE16, SE17, SE21, SE22 — and have submitted mansard applications across the borough. Our heritage statement and design-and-access statement are included in every mansard package.
Southwark's georgian and Regency in Bermondsey and Borough 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 Southwark 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 Southwark 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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