Planning permission in London for homes and small developments

“For most London projects, planning success begins before the application is submitted. The important work is understanding the property, its planning history, local guidance and neighbour context, then developing a design that makes a clear case for the changes the homeowner needs.”

— George Omalianakis, Chartered Architect and RIBA Conservation Registrant

Do you need planning permission in London?

You will normally need planning permission when a proposal falls outside permitted development rights, changes the use or number of homes, affects a flat, alters a listed building, or involves a new residential development. The answer depends on the property, the work proposed and any restrictions applying to the site.

The government describes planning permission as the consent normally required for new buildings and major changes to existing buildings or land.

In practice, the boundary between work that needs an application and work that may be permitted automatically can be less obvious, particularly in London’s older housing stock and conservation areas. See the government’s plain English guide to the planning system.

London residential projects that commonly need a planning application

• rear, side or wraparound extensions outside permitted development limits
• two-storey extensions and larger roof alterations
• mansard roofs, raised ridges and substantial dormer extensions
• external alterations and extensions to flats and maisonettes
• the subdivision of a house into flats or the amalgamation of separate homes
• changes of use and commercial-to-residential conversions
• new houses on infill, backland or side plots
• small residential schemes creating additional homes
• works affected by conservation-area controls or an Article 4 Direction
• alterations or extensions affecting a listed building

This is not a definitive checklist. A modest-looking alteration can require permission because the property is a flat, permitted development rights have been removed, or an earlier planning condition restricts future work.

Equally, some substantial house extensions can proceed under permitted development when every limit and condition is met.

Planning permission for conservation areas and listed buildings

Heritage status does not prevent a home from changing, but it makes a clear understanding of significance and context particularly important. The aim is to identify what is valuable about the building or area, then develop alterations that improve the home without eroding that character.

Planning permission, permitted development and other approvals

These approval routes deal with different questions. A project may need more than one, and receiving one approval does not remove the need for another.

Listed Building Consent

What it deals with

How work affects the special architectural or historic interest of a listed building.

Who assesses it

Your borough’s planning and conservation service.

How GOAStudio can help

Conservation-led design, heritage information, drawings and application management

If your proposal may fall within permitted development rights, our permitted development architectural service explains how we assess the rules and prepare Lawful Development Certificate applications. After planning, our Building Regulations architectural service can take the project into coordinated technical design.

How do London councils assess planning applications?

London boroughs assess applications against national policy, the London Plan, their own Local Plan and relevant design or heritage guidance. They also consider the physical context of the property and the effect of the proposal on neighbours and the wider area.

The planning history of the street can be useful, but it is not a guarantee that an apparently similar proposal will be approved. Differences in plot shape, extension depth, orientation, windows, neighbouring layouts or conservation context can lead to a different assessment.

What planning officers usually look at

• Scale and massing: whether the addition is proportionate to the original property and its surroundings
• Daylight, outlook and enclosure: whether neighbouring rooms or gardens would be unreasonably affected
• Privacy: the relationship between new windows, roof terraces, neighbouring homes and gardens
• Design and materials: how the new work responds to the original building and street
• Heritage: whether the significance of a conservation area or listed building is preserved or enhanced
• Quality of accommodation: for conversions and new homes, the adequacy of space, light, outlook, access and amenity
• Sustainability: energy, overheating, drainage, biodiversity and other borough-specific environmental requirements

GOAStudio has prepared borough-specific architect and planning guides that bring together relevant council guidance and examples of residential work. These can help you understand the broad local position, although property-specific advice is still necessary before relying on a particular route.

Core planning information sources

• GOV.UK: Plain English guide to the planning system
• Planning Portal: Do you need planning permission?
• Planning Portal: Permitted development rights
• GOV.UK: Building Regulations approval
• Historic England: Listed building consent

For a fuller explanation of applications, assessment and timescales, read our guide to how planning permission works in London.

Planning work by GOAStudio across London

Good planning advice is most useful when it is grounded in real properties and decisions. The examples below show how the balance between homeowner needs, local character and planning policy changes from one project to another.

Noel Park Conservation Area, Haringey: rear extension to a family home

Homeowner aim: enlarge a restricted kitchen and dining area, improve natural light and create a better relationship with the garden.

Planning context: a terraced house within the Noel Park Conservation Area, where the scale and appearance of the rear extension needed to preserve the area’s character and avoid unreasonable effects on neighbours.

Approach and outcome: GOAStudio designed a full-width 3.5m-deep single-storey extension. Haringey concluded that its scale was subordinate, consistent with the pattern of rear development and acceptable in its effect on the conservation area and neighbouring amenity. Planning permission was granted.

Read the Noel Park Conservation Area planning case study.

Orford Road Conservation Area, Waltham Forest: window replacement

Homeowner aim: replace ageing windows and improve everyday comfort while retaining an appearance appropriate to the period flat and street.

Planning context: a first-floor flat within the Orford Road Conservation Area, where window proportions, finish, sightlines and detailing were material considerations.

Approach and outcome: the proposed sash windows were selected and detailed to respond to the appearance of Victorian timber windows and to the established one-over-one pattern visible nearby. Waltham Forest granted planning permission.

Read the Waltham Forest window-replacement planning case study.

West Kensington W14: roof extension and conversion to two flats

Client aim: convert and extend an existing upper-floor home to create two residential units, while improving the building fabric and internal comfort.

Planning context: an existing property in the Gunter Estate Conservation Area, requiring a carefully proportioned roof extension, appropriate materials, suitable residential layouts and a considered approach to window replacement and retrofit.

GOAStudio approach: the proposal combined a dark grey zinc-clad roof extension with conservation rooflights, revised windows, two residential layouts and fabric improvements appropriate to the existing building. It demonstrates how development potential, heritage context and healthier, more comfortable accommodation can be considered together.

Read the West Kensington residential conversion case study.

Planning services for small residential developments

GOAStudio also works with small residential developers, landowners and selected self-build clients on conversions, extensions, changes of use, infill sites and new-build schemes of up to around 10 homes.

For these projects, planning strategy begins with feasibility. We assess site capacity, neighbouring amenity, access, outlook, heritage, design quality and the standards that will apply to any new homes. This helps you compare options and understand risk before committing to a land purchase or a fully developed application.

Our dedicated architects for property developments in London page explains this service, including early site appraisal, conversions, change of use and small new-build schemes.

For regional project examples and local routes into our borough guidance, see our North London residential architect services.

Frequently asked questions about planning permission in London

What does a planning permission architect in London do?

A planning permission architect assesses the site and planning context, develops the architectural design, prepares the necessary drawings and supporting information, submits the application and normally acts as the client’s agent during the council’s assessment. The architect’s value lies not only in presenting the application but in shaping a proposal that balances the client’s needs with the property, neighbours and relevant planning guidance.

Do I legally need an architect to submit a planning application?

No. A homeowner can submit a planning application without appointing an architect. However, residential projects often involve design, measurement, policy and technical judgements that are difficult to resolve through forms alone. Professional input is particularly useful for larger extensions, flats, conservation areas, listed buildings, conversions and previously refused schemes.

What is included in GOAStudio’s planning application service?

The scope usually includes a measured survey, existing drawings, concept and developed design, proposed planning drawings, relevant supporting information, submission and proportionate liaison during the council’s assessment. We confirm the precise scope and fee before appointment because the requirements for a straightforward house extension differ from those for a listed building or residential development.

How much do architectural planning services cost?

Fees depend on the property, project complexity, planning sensitivity and amount of design work required. Following the free initial Feasibility Review, we explain the recommended service and provide a tailored fee proposal. If you need detailed property-specific advice before making a wider appointment, the standalone two-hour Home Consultation costs £250 + VAT.

How long does planning permission in London take?

The statutory target for most householder and other non-major applications is normally eight weeks from validation. The overall period is longer because survey, design and application preparation take place first, and councils may request an extension of time. More complex applications, listed buildings and schemes requiring additional reports can take longer.

Can an architect guarantee planning permission?

No architect can responsibly guarantee planning permission because the decision rests with the Local Planning Authority. An experienced architect can identify risk, develop a policy-aware design, prepare accurate information and make a clear case for the proposal. Early advice can also help you avoid pursuing options that appear unlikely to receive support.

Can GOAStudio help after a previous planning refusal?

Yes. We can review the refusal reasons, submitted drawings, officer report, planning history and current policy position. We will then advise whether the more proportionate route appears to be a revised design, further supporting evidence or an appeal. A different design response is often more useful than simply resubmitting the same scheme.

Do I need both planning permission and Building Regulations approval?

Many projects need both. Planning permission considers the acceptability of the development, while Building Regulations deal with how the work is designed and constructed safely. They are separate systems, and receiving planning permission does not mean that the technical design complies with Building Regulations.

Does a conservation-area home always need planning permission?

No. Some permitted development rights still apply in conservation areas, but they may be more restricted and an Article 4 Direction may remove particular rights. The type and position of the work, property type and local controls all matter. Check the designation and relevant borough guidance before relying on permitted development.

Can GOAStudio help before I buy a property?

Yes. Early architect advice can help you understand planning history, likely constraints and whether the property appears capable of supporting the changes you have in mind. Our architect advice before buying a house in London is intended for decisions where design potential and planning risk may affect whether you proceed.

Your next step

If you are considering a London extension, renovation, heritage project or small residential development, the most useful first step is to establish what is realistic before spending money on a fully developed scheme.

Request a free Feasibility Review

Send us:
• the property address
• a brief description of the work you are considering
• a few photographs or any existing drawings
• your approximate budget range
• any timescale or previous planning history you know about

We will review the information and respond with early guidance on design potential, likely planning route and recommended next steps.