Planning Policy

Extension in Sutton

Do you need planning permission for a single-storey extension in Sutton? Here is what the permitted development rules say, how London Borough of Sutton’s designations change them, and what decides an application, grounded in the official guidance and quoted verbatim.

Modern glazed extension against a classical stone house
New glass against old stone: the extension question every authority weighs
The short answer

Do you need planning permission for a single-storey extension in Sutton?

Many single-storey rear extensions are permitted development under Class A, within set limits on depth, height and how much of the garden they cover, so no planning application is needed. In Sutton this matters: the borough has 15 conservation areas, and inside those the permitted development route narrows or is removed, so a single-storey extension can need a full application where it would not two streets away.

1.0: The permitted development position

The starting point

Many single-storey rear extensions are permitted development under Class A, within set limits on depth, height and how much of the garden they cover, so no planning application is needed.

“This provides permitted development rights for the enlargement, improvement or other alteration of a house.”PD technical guidance, Class A · full text in the library → · official source →
2.0: What changes it in Sutton

How Sutton’s designations apply

Designation in SuttonPublished
Conservation areas15
Article 4 directions (PD removed)0
Listed building outlines0

Because extension depends on permitted development rights restricted on article 2(3) land, the conservation areas above are decisive: inside one, expect to need a full application. Counts are read live from planning.data.gov.uk; your report checks them against your exact address.

3.0: How it’s decided

What Sutton weighs

Where an application is needed, design does the deciding: depth against the neighbouring rear walls, loss of light, roof form, and materials against the parent building.

As a London borough, London Borough of Sutton also decides against the London Plan 2021 (the strategic policy layer for all 33 boroughs), alongside national policy and its own Local Plan.

Read the full extension guide →

4.0: A worked example

See a single-storey extension in a real report

London’s most common project: a kitchen extension behind a Victorian terrace in a conservation area with an Article 4 direction. 262 nearby decisions, 81% approved.

Read the rear extension in clapham case study →

Your report

Get a planning report for your Sutton address

A Planning Policy report reads the designations on your exact Sutton address, quotes the London Borough of Sutton and national policies that apply to a single-storey extension, and (on Pro) shows decided applications nearby with outcomes.

5.0: Questions

Extension in Sutton, answered

Do I need planning permission for a single-storey extension in Sutton?
Many single-storey rear extensions are permitted development under Class A, within set limits on depth, height and how much of the garden they cover, so no planning application is needed. In Sutton this matters: the borough has 15 conservation areas, and inside those the permitted development route narrows or is removed, so a single-storey extension can need a full application where it would not two streets away.
Does a conservation area affect a single-storey extension in Sutton?
Yes. extension relies on permitted development rights that are restricted on article 2(3) land, which includes conservation areas. London Borough of Sutton has 15 of them, so inside a boundary you are more likely to need a full application.
How does Sutton decide a extension application?
Where an application is needed, design does the deciding: depth against the neighbouring rear walls, loss of light, roof form, and materials against the parent building. A Planning Policy report quotes the specific London Borough of Sutton Local Plan and national policies that apply, verbatim, and shows decided applications nearby.
6.0: More for Sutton

Other projects in Sutton