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Richmond upon Thames · Rear Extension · 2026

Rear Extension Planning Permission in Richmond upon Thames: 2026 Guide

Richmond upon Thames has one of London's highest conservation area coverages at 48%, which affects many rear extension proposals. Householder approvals in Richmond upon Thames run at around 72% with an average decision time of 11 weeks.

Verdict
Depends on constraints

In Richmond upon Thames, whether a rear extension needs planning permission depends on specific constraints — conservation area, Article 4, listed status or flood risk. Check your address to see which apply.

Planning Constraints in Richmond upon Thames for Rear Extension

Conservation area coverage
48%
Approval rate (Richmond upon Thames)
72%
Avg. decision time
11 weeks
Article 4 directions
1
Nearly half the borough in conservation areas
Richmond Park and Kew Gardens World Heritage Site
Local Plan design codes apply
Article 4 directions in Richmond upon Thames
  • Article 4 restricting small HMOs in specified areas

Permitted Development Rules

Rear extensions are permitted development for houses (not flats) within specific size and height limits set by the GPDO, Schedule 2, Part 1, Class A.

  • Single-storey: max 4m deep for detached, 3m for semi or terraced (or up to 8m/6m under the Larger Home Extension prior approval route).
  • Maximum eaves height 3m if within 2m of a boundary.
  • Maximum overall height 4m.
  • Materials must be similar in appearance to the existing house.
  • No part of the extension may extend beyond the principal elevation fronting a highway.
  • Total extended footprint cannot exceed 50% of the original curtilage.
  • Two-storey extensions must be at least 7m from the rear boundary and no higher than the main roof.

Read the full rear extension planning guide for the national rules and application process.

Recent Rear Extension Decisions in Richmond upon Thames

The CanUBuild checker surfaces real recent applications close to your address — approvals and refusals — so you can see what the planning officers at Richmond upon Thames Council have approved for comparable schemes. Nearby precedent is one of the strongest signals for your own chances.

Frequently Asked Questions

Do I need planning permission for a rear extension in Richmond upon Thames?

In Richmond upon Thames, the answer depends on whether your property sits in a conservation area (48% of the borough), is listed, or falls within an Article 4 direction. Most rear extension proposals are permitted development for houses when they stay within GPDO limits and no local constraint applies. Check your exact address with the CanUBuild checker before spending on drawings.

Can I build a rear extension in a conservation area in Richmond upon Thames?

Conservation areas in Richmond upon Thames typically remove several permitted development freedoms. For a rear extension, the Larger Home Extension route and some external alterations do not apply, so a full householder application is usually required. Planning officers at Richmond upon Thames Council assess conservation area proposals against the specific character appraisal for the street.

How long does a rear extension application take to decide in Richmond upon Thames?

Richmond upon Thames Council currently averages around 11 weeks for householder applications. Complex rear extension proposals — particularly those in conservation areas or on listed buildings — can take longer. Prior approval decisions for Larger Home Extensions are typically issued in 42 days.

How big can a rear extension be in Richmond upon Thames under permitted development?

A single-storey rear extension on a house in Richmond upon Thames can be up to 4m deep (detached) or 3m deep (semi/terraced) under standard PD. The Larger Home Extension prior approval route extends this to 8m and 6m respectively, but is not available in conservation areas — which cover 48% of Richmond upon Thames.

Next step

Check your specific address in Richmond upon Thames

Address-level constraints and recent decisions around the corner. No drawings needed.