ArchLocal Authority Profile
London Borough of Southwark
Adopted Documents We Assess Against
Development plan: Southwark Plan 2022 (adopted 23 February 2022)
| Document | Type | Version | Monitor Status |
|---|---|---|---|
| Southwark Plan 2022 | Local Plan | Adopted 23 February 2022 | Not yet checked |
| Householder Supplementary Planning Document | Residential Extensions SPD | 2025 | Current checked 4 August 2026 |
Documents are re-checked against the council's own website weekly. A detected change flags "Policy Update Available" for human review — live assessment standards are never replaced automatically.
London Borough of Southwark standards at a glance
11 numeric standards taken from London Borough of Southwark's own adopted documents, each shown with the paragraph it comes from. Figures differ between councils — these are this one's.
Rear extension depth
Side extension form
Amenity neighbouring
Roof form
Amenity space
Standards are what the council normally expects, not a guarantee. A scheme outside them can still be approved on its merits, and one inside them can still be refused for another reason.
Authored Policy Library
17 local policy checks, each citation-locked to the adopted document. National policy (NPPF, national space and daylight standards) applies alongside these.
Southwark Plan 2022
- Southwark Plan Policies P13 and P14 — Design character (provisional citation) Southwark will judge your extension against their design policies P13 and P14. Their Householder SPD is the practical reference for what they expect.
- Southwark Plan 2022 (residential amenity policies) — Amenity neighbouring (provisional citation) Southwark will look at the effect on your neighbours' light, outlook and privacy, using the BRE daylight guidance. Show the relationship to their windows on your drawings.
- Southwark Householder SPD (2025) — Amenity neighbouring (3 checks) (provisional citation) The council expects a roof terrace to be set back at least 1.5m from the rear elevation. The council expects a roof terrace to be set in at least 1m from the side edges. The council expects privacy screening no less than 1.7m high.
- Southwark Householder SPD (2025) — Roof form (3 checks) (provisional citation) Keep the dormer at least 1m in from the side of the roof. Keep the top of the dormer at least 0.5m below the ridge. Keep the bottom of the dormer at least 1m above the eaves.
- Southwark Householder SPD (45-degree test) — Amenity neighbouring (provisional citation) Southwark measure 45 degrees sideways and upwards from your neighbour's window. This checks the sideways line; the upward one still needs looking at.
- Southwark Plan 2022, private amenity space standards — Amenity space (2 checks) (provisional citation) Each new house in Southwark needs 50 square metres of private garden - and separately it has to be at least 10 metres long, so a wide shallow strip will not do. A new Southwark house needs at least 10 metres of garden length, on top of the 50 square metre area.
- Southwark Householder SPD 2025, mansard extensions — Roof form (provisional citation) Keep the front slope of a mansard at 70 degrees or shallower, sitting behind the parapet. On a corner house it also has to turn the corner to match the parapet.
Southwark Householder SPD (2025)
- Householder SPD section 3.5.2 — Rear extension depth Southwark expect a rear extension to stay under 6 metres deep - past that they say it is likely to be refused. Between 3 and 6 metres, the side along your neighbour's boundary has to slope down and stay under 2.4 metres, and you must keep at least half the rear garden.
- Householder SPD section 3.4.1 — Side extension form Southwark want a side extension set back 1.5 metres from the front wall, so it looks like an addition rather than making the house look wider.
- Householder SPD section 3.6.7 — Amenity neighbouring If you want a roof terrace, Southwark expect it set back 1.5 metres from the rear wall and 1 metre from the sides, with screening at least 1.7 metres high. Overlooking is what normally sinks a roof terrace.
- Householder SPD section 3.6.2 — Heritage constraints In a Southwark conservation area a dormer needs to sit well within the roof - half a metre below the ridge, a metre up from the eaves and a metre in from each side - so the roof still looks like a roof.
- Householder SPD section 3.2.6 — Amenity neighbouring Southwark draw a 45-degree line from the middle of your neighbour's window, and a 25-degree one upwards. If your extension crosses either, expect to be asked for a daylight report.