Richmond Extensions 2026: Planning Guide, Costs & Permitted Development

Richmond upon Thames: What Kind of Borough Is It?

Richmond upon Thames is unlike any other London borough when it comes to planning. It is consistently rated among the most environmentally sensitive and conservation-active local authorities in England. With 72 designated conservation areas, significant stretches of Green Belt and Metropolitan Open Land, a protected river corridor, and one of the highest concentrations of listed buildings in outer London, it is a borough where planning constraints shape almost every extension project.

The housing stock reflects this character. Richmond town itself has Georgian and Victorian properties set along the Thames and around Richmond Green — some of the most formally composed residential streets in London. Kew and Kew Green have late Georgian terraces and detached houses with generous garden plots. Twickenham offers substantial Edwardian and late Victorian semis alongside the river. Ham and Petersham are dominated by grand detached properties and quiet, village-character streets with little commercial intrusion. East Sheen and Barnes, closer to the South Circular, have large Victorian and Edwardian houses in leafy suburban settings.

Hampton, Hampton Wick, and Teddington — further south and west — shift toward 1930s and post-war housing with more permissive planning conditions and larger garden plots. But even here, conservation area designations and Article 4 directions affect a substantial proportion of properties. Understanding which planning regime applies to your specific address is essential before any design work begins.

Richmond's Local Plan and Extensions Policy

The Richmond upon Thames Local Plan (adopted July 2018) is the primary planning framework for the borough. It requires all development — including residential extensions — to be of high architectural and urban design quality that respects local character. The plan places particular emphasis on heritage, the Thames character, biodiversity, and the spaces between buildings.

For homeowners, the key supporting document is the House Extensions and External Alterations Supplementary Planning Document (SPD). Adopted in 2015 and read alongside the Local Plan, this document sets out the design principles Richmond applies to all residential extensions. A revised draft SPD has been consulted on and, once formally adopted, will replace the 2015 version. Always check the council's website for the current status.

Core design principles from the Richmond SPD

• Subordinate massing: Extensions must be visually subordinate to the original dwelling in height, width, and bulk — the host building should read as the primary structure
• Complementary or contrasting materials: Materials must either match the original building fabric or be of demonstrably high quality that forms a deliberate contemporary contrast — poorly chosen materials are a common reason for refusal in Richmond
• Neighbour amenity: Loss of light, outlook, and privacy to adjoining properties is assessed carefully — the 45-degree daylight test applies in most cases
• Space between buildings: Richmond places specific emphasis on maintaining gaps between properties — side extensions that would close a gap between houses are generally resisted
• Biodiversity: Richmond's Local Plan requires even small-scale extensions to consider biodiversity — swift bricks, bat boxes, and green roofs are increasingly expected in pre-application discussions

Conservation Areas and Article 4 Directions

Richmond upon Thames has 72 designated conservation areas — an extraordinary figure that underscores just how much of the borough is protected. In many of these areas, the council has applied Article 4 directions that remove permitted development rights for external alterations. This means that work which would normally proceed without any planning application — replacing windows, adding a rear extension, re-roofing — requires formal permission in these areas.

Richmond Hill Conservation Area

The Richmond Hill Conservation Area is one of the most carefully protected in the borough. First designated in 1969 and extended several times since, it covers the slopes and terraces leading up to Richmond Hill itself — a landscape that is also a Registered Park and Garden and benefits from one of the few views in England protected by an Act of Parliament (the Richmond Hill and River Thames Act 1902). Extensions here face the highest level of scrutiny in the borough.

The dominant building character is late Georgian and Regency stucco and brick terraces, with formal proportions and well-maintained garden settings. Extensions to properties on the Hill must not compromise the view corridors and must maintain the historic roofline and massing of the terrace or street. Pre-application advice is essential before any scheme is designed.

Kew Green and Kew Conservation Areas

Kew Green is one of the earliest conservation areas in the borough, designated in 1969. It covers the formal green and the historic houses surrounding it — a tight-knit group of Georgian and early Victorian properties, several of which are listed. Extensions here are exceptional; most properties have been fully extended to their limits and further additions face very high design expectations.

The wider Kew residential area, with its mix of Edwardian and Victorian terraces and semis, also falls partly within conservation area designations. Proximity to the Royal Botanic Gardens at Kew — a UNESCO World Heritage Site — means that heritage considerations extend beyond the formal conservation area boundaries in practice.

Petersham and Ham Conservation Areas

Petersham has one of the most distinct village characters anywhere in London. Designated in 1969, the conservation area covers a genuine rural-feeling settlement — detached houses and cottages set along narrow lanes, with Ham Common and Richmond Park immediately adjacent. Extensions here must maintain the open, uncluttered character of the area and its village scale.

Ham Common is separately designated and covers the formal green and surrounding properties — large Edwardian and late Victorian houses with generous plot sizes. Extensions are possible here on the right properties, but massing and materials are closely scrutinised. Many properties adjoin or back onto Metropolitan Open Land, adding a further layer of constraint.

Twickenham and Twickenham Riverside

Twickenham has several conservation areas, including Twickenham Riverside, Twickenham Green, and the historic core of Twickenham town. The riverside properties in particular — Georgian townhouses and villas on the banks of the Thames — face strict controls. Extensions must not disrupt the historic roofline or skyline when viewed from the river. The Article 4 direction in force across Twickenham's conservation areas means that even modest alterations require planning permission.

East Sheen and Barnes

East Sheen has a number of conservation areas covering its Victorian and Edwardian residential streets. The character here is more suburban than central Richmond — large, detached and semi-detached houses with garden plots — but the conservation area designations and Article 4 directions still apply to a significant proportion of properties. Barnes is similarly well-protected, with the Barnes Village Conservation Area and the Barnes Common area both carrying Article 4 directions.

Summary: Conservation areas by neighbourhood

Green Belt and Metropolitan Open Land

Richmond upon Thames contains significant stretches of Green Belt and Metropolitan Open Land (MOL), particularly around Richmond Park, Ham Common, Petersham, and along the Thames. These designations carry important restrictions for extensions.

Green Belt extensions

The National Planning Policy Framework (NPPF) treats extensions within the Green Belt as potentially inappropriate development unless they do not result in a disproportionate addition to the original building. Richmond Council interprets this strictly: extensions to Green Belt properties must not materially increase the built footprint of the original building in a way that would conflict with the openness of the Green Belt.

In practice, most councils allow extensions of up to around 20–30% of the original building volume on Green Belt sites, though Richmond sets this threshold at the lower end. Any extension on a Green Belt property should be assessed against the original footprint at the time the property was first built — not its current footprint if it has already been extended.

Metropolitan Open Land

Metropolitan Open Land carries equivalent protection to the Green Belt under the London Plan. Properties adjoining or within MOL — particularly in Ham, Petersham, and near Richmond Park — face additional scrutiny on any extension that could affect the openness of the designated land. Extensions on MOL itself are generally resisted; extensions to properties immediately adjacent need careful justification.

Permitted Development in Richmond

Given the extent of conservation area coverage and Article 4 directions across Richmond, permitted development rights are more restricted here than in most other London boroughs. Properties outside conservation areas — particularly in Hampton, parts of Teddington, and the less-protected parts of Twickenham — can still benefit from the standard national permitted development rules for householders where Article 4 directions do not apply.

The Planning Process in Richmond

Standard householder planning applications in Richmond are decided within 8 weeks. Applications in conservation areas or involving listed buildings can take longer, and complex or sensitive cases may be referred to the planning committee rather than decided by officers under delegated powers. Richmond is known for thorough officer assessment; a well-prepared application with good supporting documentation is more likely to be approved without amendments or delays.

Pre-application advice

Richmond offers a pre-application advice service for homeowners. This is a paid service through which a planning officer provides written feedback on a proposed scheme before a formal application is submitted. For conservation area extensions, complex sites, or listed buildings, pre-application advice is not merely useful — it is strongly advisable. Officers will indicate what materials, massing, and design approach they are likely to support, which significantly reduces the risk of refusal.

For extensions in Richmond Hill, Petersham, Kew Green, and other high-sensitivity conservation areas, pre-application engagement with the council is considered best practice by experienced architects working in the borough.

Application fees (2026)

• Householder application: £258 (England, from December 2023)
• Prior approval (large rear extension): £120
• Listed building consent: No charge (fee-exempt)

Required supporting documents

Richmond requires detailed submissions for conservation area applications. Typically this includes: existing and proposed floor plans and elevations at 1:50, elevations of adjacent buildings at 1:50 or 1:100, full details of proposed materials with manufacturer specifications, and a heritage statement justifying the design approach in the context of the conservation area character appraisal. Applications without this documentation are likely to be validated as invalid and returned before processing begins.

Extension Costs in Richmond 2026

All costs below are inclusive of VAT at 20% and reflect 2026 market rates for west and south-west London contractors. Richmond sits in a high cost band for London — typically 15–25% above south-east London boroughs and at the upper end of the outer London range. The combination of high labour rates, premium materials expectations, and the additional design and documentation requirements for conservation area applications adds meaningful cost compared to less-protected boroughs.

Additional professional and statutory costs

• Architect or architectural designer: £5,000–£15,000 (typically 8–12% of build cost; higher for complex conservation area schemes)
• Structural engineer: £2,000–£4,000
• Planning application fee: £258 (householder)
• Party wall surveyor: £1,500–£3,500 per adjoining owner (particularly relevant for terraced and semi-detached properties in Kew, Twickenham, and East Sheen)
• Building Control: £900–£2,500 depending on project scale
• Heritage statement: £1,500–£3,500 (required for listed buildings and most conservation area applications in Richmond)

Common Extension Types by Neighbourhood

Richmond and Richmond Hill: rear extensions to Georgian and Victorian properties

Properties in and around Richmond town centre are predominantly Georgian and Victorian in character. Extensions are invariably to the rear — front and side elevations are typically protected by conservation area controls and Article 4 directions. Rear single-storey kitchen and dining extensions, often with large roof lights and sliding or pivoting glazed doors opening onto the garden, are the most common type. These are typically 3–4m deep and require a planning application. High-quality contemporary design — dark-frame steel glazing, Corten steel, or carefully proportioned brick — is generally supported by officers where it demonstrates design quality.

Kew: rear extensions and loft conversions to Edwardian semis

Kew's residential streets — away from Kew Green itself — are predominantly Edwardian semis and Victorian terraces with good garden depth. Rear extensions and dormer loft conversions are the most common projects. Conservation area coverage is extensive, and the proximity to the World Heritage Site at Kew Gardens adds an additional layer of sensitivity to anything visible from public viewpoints. Side return extensions are popular where the property has a usable side passage, typically filling the narrow gap between the house and the boundary wall to create an enlarged kitchen-dining room on the ground floor.

Twickenham: extensions to substantial Victorian and Edwardian houses

Twickenham has some of the largest Victorian and Edwardian properties in the borough — substantial semis and detached houses on generous plots, particularly in the streets around Twickenham Green and St Margarets. These properties often lend themselves to two-storey rear extensions or side extensions. However, Article 4 directions across most of Twickenham's conservation areas mean that planning permission is required for most external alterations. The generous plot sizes mean there is often scope for extensions of meaningful scale, subject to design quality.

Ham and Petersham: limited opportunities, high design scrutiny

Ham and Petersham present some of the most restricted extension environments in the borough. The village character of Petersham, the adjacency to Richmond Park and Ham Common, and the prevalence of listed buildings mean that extensions here face exceptional scrutiny. Where extensions are possible — typically modest single-storey rear additions — they must be designed with extreme sensitivity to the existing building and its setting. Pre-application advice is essential.

East Sheen and Barnes: Victorian and Edwardian suburban extensions

East Sheen and Barnes offer slightly more flexibility than the central Richmond areas, with larger Victorian and Edwardian detached and semi-detached houses on generous plots. Rear extensions — typically 3–5m deep single-storey additions — and side extensions are common. Conservation area coverage is still substantial, and Article 4 directions apply to most streets, meaning planning permission is usually required. The character of these areas — well-maintained suburban streets with consistent building lines — means that design quality and material selection remain important.

Hampton and Teddington: more permissive outer suburban areas

Hampton, Hampton Wick, and Teddington — further from the river and central Richmond — have more varied housing stock, including 1930s and post-war semis alongside Victorian terraces. Conservation area coverage is less extensive here, and some streets retain permitted development rights. Single-storey rear extensions up to 6m deep may proceed without planning permission on detached properties in these areas, subject to the standard height and materials conditions. Always verify your specific address before assuming.

Planning Tips for Richmond Extensions

• Use pre-application advice for all conservation area schemes. Richmond has 72 conservation areas and officers are experienced with the specific design expectations of each. A pre-application conversation significantly reduces the risk of refusal on materials, scale, or design approach. The cost of pre-app advice is negligible compared to the cost of a refused application.
• Read the conservation area character appraisal for your area. Richmond has published detailed character appraisals for most of its 72 conservation areas. These documents identify the key materials, building forms, and spatial qualities that officers will be assessing your scheme against. Architects unfamiliar with the borough should read these before beginning any design work.
• Never assume permitted development applies. With 72 conservation areas and widespread Article 4 directions, the majority of properties in Richmond are subject to some form of planning constraint that removes or restricts permitted development rights. Use Richmond's online planning map or our free checker to verify your specific address before starting any design.
• Budget for a heritage statement in conservation areas. Richmond officers typically expect a written heritage statement justifying the design of any extension in a conservation area — particularly for listed buildings or properties in the most sensitive areas such as Richmond Hill, Kew Green, and Petersham. This is a specialist document that should be prepared by an architect or heritage consultant.
• Party wall notices are essential for all semi-detached and terraced properties. The Victorian and Edwardian semis and terraces that dominate most of Richmond's conservation areas all have shared party walls. You must serve notice on adjoining owners before beginning any excavation or structural work to a shared wall. Allow 2–4 months for this process if neighbours appoint their own surveyor.
• Check for trees before commissioning any design. Richmond has an exceptional number of protected trees — both TPO-protected and those in conservation areas that require council consent before works. Mature trees can significantly constrain extension design, particularly foundations and drainage. A tree survey by an arboriculturalist is advisable early in the design process for any scheme where tree proximity is a factor.