Room extension drawings in Dulwich
For a room extension in Dulwich SE21, first check whether your street is in a conservation area: it decides which routes are open. Southwark, the council for most SE21 addresses, granted 95% of its 558 householder applications in the four quarters to 2026 Q2 (our analysis of MHCLG planning application statistics, table PS2). Rear extension drawings start from £695.
Fixed fee from £495 drawings + £200 survey (£695 total) · all prices
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Which council decides your extension
We use Southwark's figures for SE21. A few addresses near the borough boundary belong to a neighbouring council, so confirm yours with the postcode lookup on GOV.UK before relying on any local figure.
In Southwark, 97% of householder decisions outside prior approvals came within 8 weeks (our analysis of MHCLG planning application statistics, table PS2). That is the council's performance across the borough, and it is not a timetable for your application.
Conservation areas change what you can build
The national register lists 56 conservation-area entries for Southwark (our analysis of the MHCLG Planning Data Platform conservation-area dataset), and your street may be inside one. The register may not match the council's list, so look at Southwark's conservation area map for your own street.
Inside a conservation area the larger home extension route is not available, and the council looks closely at what the extension does to the street scene. Our conservation area extension rules guide lists the extra drawings that are often needed, and the Article 4 direction guide covers rights that a council has withdrawn.
The Planning Inspectorate decided 72 householder appeals for Southwark between 2021 and 2026 and allowed 31% (our analysis of the Planning Inspectorate Casework Database, release 2609).
Prior approval is the exception, not the rule
Southwark determined only 14 larger home extension prior approvals over the eight quarters from 2024 Q3 to 2026 Q2 (our analysis of MHCLG planning application statistics, table PS1). With so few cases there is no meaningful rate, so most Dulwich extensions that need more than the usual allowance go through a householder application.
A house that is not detached may extend 3 metres beyond the original rear wall as permitted development, inside a conservation area or not, unless an Article 4 direction has removed the right. Only outside a conservation area can it go to 6 metres through prior approval (GPDO 2015, Schedule 2, Part 1, Class A).
Appeals, covenants and cost
The Planning Inspectorate decided 72 householder appeals for Southwark between 2021 and 2026 and allowed 31% (our analysis of the Planning Inspectorate Casework Database, release 2609). Planning is also not the only control: some properties carry covenants or estate rules in their title, so check yours before you spend on design.
Southwark's householder fee is £548 from 1 April 2026. Our starting fixed fee for single-storey rear extension drawings is £695, with other prices on the pricing page. For the wider process, see planning permission in Southwark and the London house extension drawings hub.
Sources
Every figure on this page, where it comes from and a link to the original.
| Figure | Source | Link |
|---|---|---|
| £695 | DrawingsDirect starting fixed fee for single-storey rear extension drawings (survey and planning or permitted development drawings), from the published price list | drawingsdirect.co.uk |
| 3 metres | GPDO 2015 Sch 2 Pt 1 Class A.1(f)(i): a single-storey rear extension may extend beyond the rear wall of the original house by up to 3 metres, house other than detached (source wording: 3 metres) | www.legislation.gov.uk |
| 6 metres | GPDO 2015 Sch 2 Pt 1 Class A.1(g): larger home extension under the prior approval process (A.4), house other than detached, up to 6 metres beyond the original rear wall (source wording: 6 metres) | www.legislation.gov.uk |
| 558 | Our analysis of MHCLG planning application statistics, table PS2 (district open data table) (released 24 Sep 2026, quarters to 2026 Q2) | www.gov.uk |
| 95% | Our analysis of MHCLG planning application statistics, table PS2 (district open data table) (released 24 Sep 2026, quarters to 2026 Q2) | www.gov.uk |
| 97% | Our analysis of MHCLG planning application statistics, table PS2 (district open data table) (released 24 Sep 2026, quarters to 2026 Q2) | www.gov.uk |
| 72 | Our analysis of Planning Inspectorate Casework Database (released 1 Oct 2026 (Casework Database 2609)) | www.gov.uk |
| 31% | Our analysis of Planning Inspectorate Casework Database (released 1 Oct 2026 (Casework Database 2609)) | www.gov.uk |
| 56 | Our analysis of MHCLG Planning Data Platform conservation-area and article-4-direction datasets (bulk snapshot retrieved 14 Aug 2026) | www.planning.data.gov.uk |
| 14 | Our analysis of MHCLG planning application statistics, table PS1 (district open data table) (released 24 Sep 2026, quarters to 2026 Q2) | www.gov.uk |
| £548 | Fees for planning applications in England from 1 April 2026 (MHCLG, SI 2012/2920 as annually indexed), category 6(1): householder application for the enlargement, improvement or alteration of a single dwellinghouse (source wording: £548) | assets.publishing.service.gov.uk |
Questions people ask
Do I need planning permission for a room extension in Dulwich?
Does Southwark approve rear extensions in Dulwich?
How much do house extension drawings cost in Dulwich?
Photographs: Fernweh (CC BY-SA 2.0).
