Which Lambeth postcodes does this mansard roof extension service cover?
Lambeth's postcodes are unusually shared: SE1, SE5, SE19, SW2, SW4, SW8 and SW16 between them touch five neighbouring authorities. The table sets out what each district is built from and who would validate a roof scheme there. The money column is the government's 2026 application fee, and has nothing to do with our design fee.
| Postcode | Area | Dominant stock | What it means for a mansard roof extension |
|---|
| SW2 | Brixton Hill / Tulse Hill | Victorian terraces, post-war estates | SW2 holds Brixton Hill and Tulse Hill entirely within Lambeth, which means a single validating authority and a single Local Plan to design a roof scheme against. |
| SW4 | Clapham | Victorian terraces, Edwardian villas | Clapham is cut by the SW4 boundary between Lambeth and Wandsworth. Which council receives the application changes both the validation list and the conservation guidance applied to it. |
| SW8 | South Lambeth / Nine Elms | Victorian terraces, new-build apartments | SW8 spans South Lambeth and Nine Elms across the Wandsworth line. Either authority may end up validating a roof scheme, and the division is made address by address, not by neighbourhood. |
| SW9 | Brixton / Stockwell | Victorian terraces, post-war estates | SW9 covers Brixton / Stockwell only; Lambeth Council handles the mansard roof extension. |
| SW16 | Streatham / Norbury | Edwardian terraces, post-war flats | SW16 is unusually fragmented: Streatham and Norbury addresses fall to Lambeth, Wandsworth, Merton or Croydon. Four validation regimes under one postcode, which is why the address is checked before anything gets drawn. |
| SE1 | Bermondsey / Borough / Waterloo | Georgian terraces, post-war flats, new-build | SE1 takes in Waterloo, Borough and Bermondsey either side of the Southwark line, so a roof scheme here needs its authority confirmed before the application is assembled. |
| SE5 | Camberwell | Georgian villas, Victorian terraces | Camberwell straddles SE5, shared between Southwark and Lambeth. We establish the deciding council from the address before design, since the two publish different expectations for roof alterations. |
| SE19 | Upper Norwood / Crystal Palace | Victorian villas, Edwardian terraces | SE19 divides Upper Norwood and Crystal Palace between Croydon and Lambeth. The postcode alone will not tell you which council validates a roof scheme here, so we resolve the address against both local plans first. |
Which Lambeth neighbourhoods suit a mansard roof extension best?
Mansard geometry is dictated by what is already on the roof. Ridge height, party wall build-up and the depth of the original butterfly or pitched structure change every few streets, and each one moves the achievable floor area by several square metres.
- Streatham (SW16) — a mansard roof extension in Streatham starts from edwardian terraces, post-war flats, and Streatham reads as Edwardian terraces, post-war flats. Edwardian parapets give a mansard a clean base line in SW16. Lambeth Council assesses Streatham mansard roof extensions against its own Streatham character guidance, and the location plan we draw for Streatham references Streatham High Road.
- Stockwell (SW9) — Victorian terraces, post-war estates defines Stockwell, where victorian terraces, post-war estates set what a mansard roof extension can do. A mansard on a Victorian terrace almost always needs full planning permission across SW9. Any Stockwell mansard roof extension is validated by Lambeth Council, with Stockwell station the usual Stockwell reference point on the site plan.
- Vauxhall (SE11, SW8) — mansard roof extension work in Vauxhall means regency terraces, modern apartments, post-war flats. Vauxhall is Regency fragments, riverside new-build. Mansards on post-war blocks are a structural and fire-strategy exercise before they are an aesthetic one throughout SE11. Lambeth Council decides the Vauxhall application, and Vauxhall Bridge anchors the Vauxhall location plan.
- West Norwood (SE27) — Victorian terraces, Edwardian villas defines West Norwood, where victorian terraces, edwardian villas set what a mansard roof extension can do. A mansard on a Victorian terrace almost always needs full planning permission across SE27. Any West Norwood mansard roof extension is validated by Lambeth Council, with West Norwood Cemetery the usual West Norwood reference point on the site plan.
- Tulse Hill (SE27, SW2) — a mansard roof extension in Tulse Hill starts from victorian villas, edwardian terraces, and Tulse Hill reads as Victorian villas, Edwardian terraces. A mansard on a Victorian terrace almost always needs full planning permission in SE27. Lambeth Council assesses Tulse Hill mansard roof extensions against its own Tulse Hill character guidance, and the location plan we draw for Tulse Hill references Tulse Hill station.
- Waterloo (SE1) — a mansard roof extension in Waterloo starts from georgian terraces, post-war flats, new-build, and Waterloo reads as Georgian fragments, post-war estates, regen. Mansards read as original on Georgian terraces in SE1. Lambeth Council assesses Waterloo mansard roof extensions against its own Waterloo character guidance, and the location plan we draw for Waterloo references Southbank Centre.
- Clapham (SW4) — a mansard roof extension in Clapham starts from victorian terraces, edwardian villas, and Clapham reads as Victorian terraces around the common. A mansard on a Victorian terrace almost always needs full planning permission in SW4. Lambeth Council assesses Clapham mansard roof extensions against its own Clapham character guidance, and the location plan we draw for Clapham references Clapham Common.
Does Lambeth planning policy restrict a mansard roof extension?
64 conservation areas cover much of the borough: Clapham Common, Herne Hill and Brixton Road are the ones owners here meet most. Inside any of them a roof scheme loses permitted development entirely. The householder application fee in England is £548 and the council then has 8 weeks. The fee for a larger householder prior approval is £249 on a 6-week prior approval, and that route is shut to you. On Clapham Common the street elevation is assessed before anything internal.
Lambeth and Article 4: Borough-wide Article 4 for HMO conversions; plus office-to-residential restrictions. A mansard roof extension planned at a SE11 address is checked against that direction first; Lambeth Council publishes the Lambeth extent, and the SE11 line rarely follows the Lambeth boundary you would expect.
What the borough is built from: 36.6% of its 148,600 homes predate 1900, measured at 31 March 2025 in the VOA's stock-of-properties data — Victorian terraces in Clapham, Brixton and Herne Hill, Georgian at Kennington, Edwardian villas, and post-war estates through parts of Streatham. Construction rather than postcode sets what a roof scheme can achieve, and on a solid-wall Victorian terrace the party wall build-up matters more than any design guide. The householder application fee in England is £548, with a statutory 8 weeks to determine.
Which neighbouring authorities border Lambeth?
- Southwark — adjoining Lambeth, with 43 conservation areas centred on SE1. A mansard roof extension on the far side of the Lambeth line is determined by Southwark Council, so the Lambeth quote for mansard roof extensions is checked against Southwark guidance before it is issued.
- Wandsworth — cross the Lambeth boundary and Wandsworth Council takes the mansard roof extension instead, applying 45 conservation areas of its own around SW8. We re-price mansard roof extensions at the Lambeth edge because Wandsworth policy and Lambeth policy rarely align on mansard roof extension depth.
- Croydon — the Croydon boundary runs against Lambeth, so a mansard roof extension a street from Lambeth is decided by Croydon Council instead. Croydon runs 24 conservation areas across CR0 and its neighbours, which is why mansard roof extensions priced for Lambeth are re-checked against Croydon policy whenever the Lambeth address sits on that edge.
- Merton — the Merton boundary runs against Lambeth, so a mansard roof extension a street from Lambeth is decided by Merton Council instead. Merton runs 28 conservation areas across SW16 and its neighbours, which is why mansard roof extensions priced for Lambeth are re-checked against Merton policy whenever the Lambeth address sits on that edge.
Sources for this Lambeth 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.
