BOROUGH · PROJECT

Rear extension in Richmond upon Thames

Planning permission, real costs and what actually gets approved

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

Sometimes under permitted development outside the conservation areas — a single-storey rear within the size limits, or larger via prior approval on unconstrained houses. Conservation coverage is among the most extensive in London, so many ordinary-looking streets still need a full application, judged against the House Extensions and External Alterations SPD. The borough-wide basement Article 4 does not itself remove rear-extension rights.

Single-storey rear extensions are unaffected by the basement Article 4, but conservation coverage is extensive — check whether the address sits in a designated area.

Richmond upon Thames is London's most conservation-dense borough among those this site covers, with designation spanning riverside, village and suburban streets from Richmond and Kew through Twickenham, Teddington and Barnes. The House Extensions and External Alterations SPD sets design expectations whether or not a house sits in a conservation area, and Thames views add landscape scrutiny near the river and on the hill. Outside the designated areas, suburban and villa stock still supports ordinary rear extensions under permitted development.

CHECK

What actually applies in Richmond upon Thames

Conservation areas in Richmond upon Thames

Real · planning.data.gov.uk

Every designated conservation area in Richmond upon Thames from the official dataset — inside one, permitted development narrows and design scrutiny rises.

  • Amyand Park Road
  • Barnes Common
  • Barnes Green
  • Belmont Road
  • Beresford Avenue
  • Blackmore's Grove
  • Broad Street
  • Broom Water
  • Burlington Avenue and West Park Road
  • Bushy Park
  • Bushy Park Gardens
  • Cambridge Park
  • Castelnau
  • Central Richmond
  • Christ Church Road
  • Church Road
  • Cole Park Road
  • Cowley Road
  • Crown Road
  • East Sheen Avenue
  • Fieldend
  • Ham Common
  • Ham House
  • Hamilton Road
  • Hampton Court Green
  • Hampton Court Park
  • Hampton Village
  • Hampton Wick
  • Hanworth Road
  • High Street Hampton Hill
  • High Street Teddington
  • Holmesdale Avenue
  • Joanna Southcott Chapel
  • Kew Foot Road
  • Kew Gardens
  • Kew Green
  • Kew Road
  • King Edwards Grove
  • Lawn Crescent
  • Madrid Road
  • Mallard Place
  • Mays Road
  • Mill Hill
  • Model Cottages
  • Mortlake
  • Mortlake Green
  • Normansfield
  • Oaklands Estate
  • Old Deer Park
  • Park Road (Teddington)
  • Parkleys Estate
  • Petersham
  • Platt's Eyot
  • Pope's Avenue
  • Queen's Road (Mortlake)
  • Queen's Road (Twickenham)
  • Richmond Green
  • Richmond Hill
  • Richmond Park
  • Richmond Riverside

…plus 26 further designated areas.

Source: planning.data.gov.uk · Open Government Licence. Boundaries are checked at address level by the area report.

Article 4 directions in Richmond upon Thames

Real · planning.data.gov.uk

No Article 4 geometry for Richmond appears in the national planning.data.gov.uk dataset, but the borough operates a significant one: a direction made in February 2017 that, from 1 April 2018, removed permitted development rights for basement and subterranean development across the whole borough except the areas of greatest flood hazard — so every basement here needs planning permission. A further direction covers parts of the flood-hazard area. Check the council's Article 4 register and basement pages for the position at a specific address.

Source: planning.data.gov.uk · Open Government Licence. Checked at address level by the area report.

Average house price
£798,928
Annual change
-0.4%

Prices: HM Land Registry UK House Price Index, December 2025 · Open Government Licence.

How often Richmond upon Thames grants householder applications: 81.7% of householder applications decided were granted (1,113 of 1,362) over 2025 Q2 to 2026 Q1 — rank 9 of 33 for lowest grant rate. London average: 85.6%. Householder applications are the class most rear extensions fall under. See the full householder approval-rate league table →
ROUTE

The planning route — PD or permission?

Permitted development (GPDO Class A) covers single-storey rear extensions up to 3m beyond the original rear wall on attached houses and 4m on detached, with a maximum height of 4m. The 'larger home extension' route extends this to 6m/8m through prior approval with neighbour consultation — but that larger route is not available in conservation areas.

In conservation areas, the basic 3m/4m single-storey rear PD allowance usually survives — what conservation-area status removes is side extensions and two-storey rear extensions. An Article 4 direction can remove more, but Camden's directions in Hampstead and Belsize target front-and-side appearance (solar panels, window changes, boundary treatments), not the single-storey rear allowance. Flats have no PD rights at all. Two-storey rear extensions in conservation areas always need full permission.

Practical rule across London: check the address first. If a conservation area or Article 4 direction applies, budget for a full householder application decided on design, neighbour daylight (the 45-degree test) and materials.

LIMITS

Permitted development limits — rear extension

Single-storey rear depth — attached house3m beyond the original rear wall
Single-storey rear depth — detached house4m beyond the original rear wall
Larger extension via prior approval6m attached / 8m detached — not in conservation areas
Maximum height (single storey)4m
Two-storey rear in a conservation areaFull planning permission required
FlatsNo permitted development rights

Limits summarise the General Permitted Development Order (Schedule 2, Part 1) as it applies in London. In Richmond upon Thames, a conservation area, Article 4 direction or listed status changes the route — the panels above show what is designated, and the address check confirms what applies at your property.

COST

How much does a rear extension cost in Richmond upon Thames?

Cost per m² (low — straightforward site)£3,000
Cost per m² (expected)£3,800
Cost per m² (high — conservation spec, hard access)£4,600+
Typical build cost (12–18m² single storey)£36,000 – £83,000
Professional fees, surveys, party wall (add)10–18% of build

Indicative London ranges calibrated from real project data. Conservation-area specifications (matching stock brick, lime mortar, bespoke glazing) and restricted rear access are the two biggest cost drivers. VAT not included.

TIME

Realistic timeline

Design and drawings4–8 weeks
Planning decision (full application)8–12 weeks (8-week statutory target)
Prior approval route, where available42 days
Party wall agreements4–10 weeks (parallel)
Build3–5 months
WATCH

What catches people out in Richmond upon Thames

Assuming permitted development because the house is not on a famous street is risky — conservation coverage is that extensive. Near the river and on Richmond Hill, height and roofline can be assessed against protected views as well as ordinary neighbour tests. Always check the address before sketching depth.

DISTRICTS

Postcode districts in Richmond upon Thames

TW9 — Richmond & Kew

TW9 covers Central Richmond, Richmond Green and Richmond Riverside, and at Kew the Kew Green and Kew Gardens conservation areas around the Royal Botanic Gardens — a World Heritage Site.

TW9 — Richmond & Kew →
TW10 — Richmond Hill, Petersham & Ham

TW10 runs from Richmond Hill — whose view over the Thames is protected by its own Act of Parliament — through the Petersham, Ham Common and Ham House conservation areas to the edge of Richmond Park.

TW10 — Richmond Hill, Petersham & Ham →
TW1 — Twickenham & St Margaret's

TW1 spans Twickenham Riverside and Twickenham Green, the St Margaret's Estate and Cole Park Road conservation areas, with Strawberry Hill nearby.

TW1 — Twickenham & St Margaret's →
TW11 — Teddington

TW11 is Teddington — the High Street Teddington and Teddington Lock conservation areas and the Broom Water riverside.

TW11 — Teddington →
SW14 — Mortlake & East Sheen

SW14 covers Mortlake and Mortlake Green, the East Sheen Avenue and Sheen Lane conservation areas, and Sheen Common.

SW14 — Mortlake & East Sheen →
SW13 — Barnes

SW13 is Barnes — riverside and common-edge streets in Richmond upon Thames, with extensive conservation coverage.

SW13 — Barnes →
TW2 — Twickenham & Whitton fringe

TW2 covers Twickenham and the Whitton fringe, spanning Richmond and Hounslow.

TW2 — Twickenham & Whitton fringe →
TW12 — Hampton

TW12 is Hampton in Richmond upon Thames — riverside and village streets with substantial conservation coverage.

TW12 — Hampton →
FAQ

Rear extension in Richmond upon Thames, asked straight

01

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

Outside the conservation areas, many houses can still use permitted development or prior approval for single-storey rear extensions. Inside a designated area, expect a full application. Check the address — coverage is extensive.
02

How much does a rear extension cost in Richmond?

Budget £3,000–£4,600+ per m², or roughly £36,000–£83,000 for a typical 12–18m² single-storey scheme, before VAT and fees. Conservation specification sits at the top of the range.
03

Does the basement Article 4 affect rear extensions?

No — the borough-wide basement direction targets subterranean development, not single-storey rear extensions. Conservation designation is the control that more often changes the rear-extension route.
04

What do protected river views mean for my project?

Near the Thames and on the hill, massing and roofline can be assessed against protected landscape views as well as conservation policy. Precedent and pre-application advice help on anything prominent.
05

Do I need a party wall agreement?

On terraced and semi-detached houses, almost always when works affect a shared wall or nearby foundations.
CHECK

What applies at your address?

Borough-level rules only narrow it down. Enter a Richmond upon Thames postcode for the live constraint check — conservation area, Article 4 and sold-price comparables, cited to source.

Check a Richmond upon Thames address

Need it in writing for one address? A planning permission report for a Richmond upon Thames property — from £59, or surveyor-reviewed from £295.

Planning Permission Checker provides planning and cost intelligence for early feasibility only. It is not legal, planning, valuation, architectural, structural, or surveying advice. All estimates are indicative and must be verified by qualified professionals before purchase, design, planning submission, or construction.

Cost estimates are indicative only — not a quotation. Final price depends on survey, specification, structure, access, party wall matters, VAT, professional fees, and contractor availability.

Planning outcomes are not guaranteed. Local planning authorities make final decisions.

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