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Property guide · Southwark

Modern flat extensions in Southwark

Purpose-built or converted flats with restricted PD rights. Internal-only alterations dominate.

Quick facts

Property type
Modern flat
Borough
Southwark
Planning authority
Southwark Council
Article 4 in force
Yes
Conservation areas
43
Drawings from
£840

Modern flat stock in Southwark responds best to extensions that respect the existing rhythm. For Victorian and Edwardian period property, side returns and rear infill are routine. For 1930s suburban, single-storey rear and loft conversions dominate. We design to the block, not the brochure.

London period house exterior with architectural character — architectural drawings in Southwark
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Where in Southwark does a modern flat project actually get determined?

Every Southwark postcode district we draw in, the stock that dominates it and the authority that validates a modern flat project there. Southwark fees below are the statutory England rates for 2026, not modern flat project estimates.

PostcodeAreaDominant stockWhat it means for a modern flat project
SE1Bermondsey / Borough / WaterlooGeorgian terraces, post-war flats, new-buildSE1 straddles a boundary: Bermondsey / Borough / Waterloo addresses fall to Southwark Council or Lambeth Council, so confirm which authority validates the modern flat project before submitting SE1 drawings.
SE5CamberwellGeorgian villas, Victorian terracesCamberwell is split at SE5. Either Southwark Council or Lambeth Council can determine a modern flat project here, so the SE5 address is checked against both policies maps first.
SE15Peckham / NunheadVictorian terraces, post-war estatesA modern flat project at an SE15 address in Peckham / Nunhead is determined by Southwark Council under its own Local Plan policies for Peckham / Nunhead.
SE16Bermondsey / RotherhitheWarehouse conversions, Georgian terraces, new-buildSE16 covers Bermondsey / Rotherhithe only; Southwark Council handles the modern flat project, and Bermondsey / Rotherhithe case officers apply the SE16 conservation-area map.
SE17WalworthPost-war estates, new-build towersSE17 covers Walworth only; Southwark Council handles the modern flat project, and Walworth case officers apply the SE17 conservation-area map.
SE21Dulwich VillageGeorgian villas, Edwardian villas (Dulwich Estate)Dulwich Village is split at SE21. Either Southwark Council or Lambeth Council can determine a modern flat project here, so the SE21 address is checked against both policies maps first.
SE22East DulwichVictorian and Edwardian terracesSE22 covers East Dulwich only; Southwark Council handles the modern flat project, and East Dulwich case officers apply the SE22 conservation-area map.
SE24Herne HillVictorian villas, Edwardian terracesHerne Hill is split at SE24. Either Lambeth Council or Southwark Council can determine a modern flat project here, so the SE24 address is checked against both policies maps first.

Which Southwark neighbourhoods suit a modern flat project best?

Roof pitch, wall build-up and plot depth change every few Southwark streets, and each one changes what a modern flat project can achieve at that address.

How do conservation areas and Article 4 affect a modern flat project in Southwark?

Conservation areas covering Southwark: Southwark Council runs 43, and Borough, Camberwell Grove, Bermondsey Street are the ones Southwark owners meet most. A modern flat project inside a Southwark conservation area loses permitted development, so the Southwark submission is a householder application at £258 decided in 8 weeks — not a £120 prior approval decided in 6 weeks. In Bermondsey Street a modern flat project is judged on the street elevation first.

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 modern flat project 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.

Southwark housing stock: 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. Read that before choosing a modern flat project route in Southwark — construction, not postcode, sets what is achievable. Modern flat projects in Southwark start at £840 on a fixed fee, or £1,750 for the Complete package covering both Southwark Council submissions.

Which neighbouring authorities border Southwark?

Sources for this Southwark modern flat project 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.

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