Rear extension drawings in Southwark from £625
Peckham, Dulwich, Camberwell and Bermondsey: Southwark’s July 2025 householder guide gives real numbers for a back extension, and we draw to them.
£625 £475 drawings + £150 survey (£625 total), no VAT to add
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The short answer
Southwark’s Householder Development SPD of July 2025 sets the lines. Extensions of 3 to 6 metres need care over neighbours, especially on the boundary, with a roof sloping down to 2.4 metres at that boundary. Over 6 metres on the boundary is likely to be refused, the recommended height is 4 metres, and no more than 50% of the rear garden should be taken. Our fee is £475 drawings + £150 survey (£625 total), no VAT to add; the council’s fee is separate.
Rear extension drawings
from £625
- Drawings
- £475
- Measured survey
- £150
- Total you pay
- £625
- VAT
- None to add
- A measured survey of the back of the house, the garden and the neighbours’ windows and extensions
- A check of the depth, height and 50% garden limit against the July 2025 SPD, and the 25 and 45 degree tests
- A check of your address against Southwark’s conservation areas and Article 4 directions
- A site plan at 1:100 or 1:50 with every adjoining building labelled and numbered, and the fire safety form the checklist asks for
- The route that fits submitted for you, and answers to the case officer
£475 drawings + £150 survey (£625 total). A starting fee: we confirm one fixed figure after checking your address. The council’s own fee, where there is one, is paid to the council.
Get my fixed feeHow a Southwark rear extension runs
Depth and garden check
We measure the garden and set your depth against the 6 metre line and the 50% limit.
Survey
We measure the rear wall, the neighbours’ windows and the boundary heights.
Design
You choose depth, height and a roof that slopes to the boundary, with the route written down.
Draw and submit
We prepare the pack to the householder checklist and submit it.
The numbers in Southwark’s 2025 guide
Section 3.5 of the Householder Development SPD says that beyond permitted development you need planning permission. Extensions between 3 and 6 metres deep must consider the impact on neighbours, especially on the boundary wall, and the council encourages a roof that slopes down towards the neighbour and stays below 2.4 metres at the boundary for the full length. Extensions over 6 metres on the boundary are likely to be refused for enclosure and loss of light. Rear extensions must not take more than 50% of the rear garden.
The recommended dimensions are a height of up to 4 metres and a depth under 6 metres. The guide also sets out the 45 and 25 degree tests used for daylight and sunlight. For example, a 5 metre kitchen on a Peckham terrace with a boundary roof dropping to 2.4 metres is within the guide; a 6.5 metre extension with a flat 3 metre parapet on the boundary is not.
Permitted development and the Sunray Estate
Under Class A a single-storey extension can be 3 metres deep on a terrace or semi and 4 metres on a detached house, or 6 and 8 metres through a larger home extension notice. The SPD says large extensions under prior approval only apply outside conservation areas, and that flats and maisonettes have no permitted development.
Southwark’s Sunray Estate Conservation Area, confirmed in 1987, is one place where extra controls apply on Sunray Avenue, Sunray Gardens, Casino Avenue and Nairne Grove. We check your road before choosing a route.
What Southwark asks for, and CIL
Southwark’s householder checklist wants a fire safety strategy or a reasonable exception form under London Plan Policy D12, CIL information, and a site plan at 1:100 or 1:50 that labels and numbers every adjoining building. Documents must hold no personal information, such as names, number plates or photographs of people, or the application can be invalidated.
Southwark’s CIL runs in three zones at £435, £218 and £54 a square metre before indexation, on 100 square metres or more of new build. A typical rear extension is below that. Mayoral CIL is in band 2.
Rear extensions in Southwark in numbers
424 of 435
Householder decisions by Southwark Council between July 2025 and June 2026 (prior approvals left out) that were made inside 8 weeks.
Source: MHCLG live table PS2, district planning application statistics, July 2025 to June 2026 (GOV.UK)
6 m
Depth over which an extension on the boundary is likely to be refused under the July 2025 Householder SPD.
Source: Householder Development SPD, July 2025, section 3.5 Rear extensions (Southwark Council)
2.4 m
Height the SPD encourages at the neighbour boundary for the full length of a 3 to 6 metre extension, with the roof sloping down to it.
Source: Householder Development SPD, July 2025, section 3.5 Rear extensions (Southwark Council)
50%
Largest share of the rear garden a rear extension should take under the SPD.
Source: Householder Development SPD, July 2025, section 3.5 Rear extensions (Southwark Council)
3 m / 4 m
Deepest single-storey extension permitted development allows; 6 and 8 metres through prior approval.
Source: GPDO 2015, Schedule 2, Part 1, Class A: enlargement of a dwellinghouse (legislation.gov.uk)
D12
London Plan policy behind the fire safety strategy or reasonable-exception form Southwark requires with every householder application.
Source: Planning checklists: householder application (Southwark Council)
1:100 or 1:50
Scale of the site plan, on which every adjoining building is labelled and numbered.
Source: Planning checklists: householder application (Southwark Council)
1987
Year the Sunray Estate Conservation Area direction was confirmed, controlling external alterations on its named streets.
Source: Article 4: Sunray Estate Conservation Area (Southwark Council)
8, 13 or 16 weeks
The estimated decision date Southwark gives after validation, depending on application type.
Source: After you apply for planning permission (Southwark Council)
£435 / £218 / £54
Southwark residential CIL per square metre in Zones 1, 2 and 3, before indexation.
Questions about rear extensions in Southwark
How deep can I go in Southwark?
Permitted development gives 3 or 4 metres. With planning permission the 2025 SPD puts the line at 6 metres on the boundary, and extensions of 3 to 6 metres need to protect neighbours.
Why does the roof need to slope to the boundary?
The SPD encourages a roof that slopes down towards the neighbour and stays below 2.4 metres at the boundary, which cuts the sense of enclosure.
Is there a limit on garden loss?
Yes. A rear extension should not take up more than 50% of the rear garden, so short gardens limit what is possible.
Do I pay CIL on a kitchen extension?
No, not normally. New-build floor area under 100 square metres is exempt unless the work creates a dwelling.
See how far your Southwark house can go
Send the address and a photo of the back. We reply with the route and a fixed fee, from £475 drawings + £150 survey (£625 total).