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Service area · City of Westminster

Architectural Designers in Westminster

Magna Studio prepares planning, listed building and Building Regulations drawings for homeowners across the City of Westminster. Our typical Westminster projects are rear extensions to stucco terraces in Pimlico and Bayswater, mews house alterations in Marylebone and Belgravia, mansards and roof extensions where the terrace allows, internal alterations to mansion flats, and single-storey basements under the council's strict policy. Every quote is a fixed fee agreed in writing before we start.

Get an instant estimatePlanning constraints

Indicative fee in two minutes. Written fixed-fee quote within 24 hours.

Planning authority
Westminster
Decision time
8 weeks statutory
Common work
Rear extension
Quote
Within 24 hours
01Local context

Typical homes we work on in Westminster

  • Stucco terraces and garden squares in Pimlico, Belgravia and Bayswater
  • Georgian townhouses and terraces in Marylebone, Mayfair, Fitzrovia and Soho
  • Mews houses behind the main terraces across Marylebone, Belgravia, Bayswater and Pimlico
  • Victorian and Edwardian mansion blocks in Marylebone, Maida Vale, St John's Wood and Victoria
  • Victorian villas and terraces in St John's Wood, Maida Vale and Queen's Park
  • Post-war council estates including Churchill Gardens, Lisson Grove and Church Street
02Planning permission

Do I need planning permission in Westminster?

Answer-first guides for the projects we see most here, with the national rules and the local constraints that change them.

03Constraints

Planning constraints in Westminster

What changes the planning route in this area. Always confirm on the council's constraints map before relying on permitted development.

Conservation areas

More than 50 conservation areas cover the great majority of Westminster's housing, including Pimlico, Belgravia, Bayswater, Maida Vale, St John's Wood and Queen's Park. Roof extensions, cladding and most external alterations need planning permission rather than permitted development. The council publishes conservation area audits that officers use to judge design.

Source · Checked 15 Sept 2026

Basement Article 4 direction and basement policy

Westminster has an Article 4 direction removing permitted development for basement excavations, and its City Plan basement policy limits new basements to a single storey beneath the house and no more than half the garden, with structural, drainage and construction management information required. Basements are common in Pimlico, Belgravia and Maida Vale but tightly controlled.

Source · Checked 15 Sept 2026

Listed buildings

Westminster has more listed buildings than any other London borough, including whole terraces and squares in Belgravia, Pimlico, Mayfair and Marylebone. Listed houses need listed building consent for almost any alteration, internal or external, and extensions to neighbours are judged on their effect on the setting of the listed terrace.

Checked 15 Sept 2026

Class MA and other Article 4 directions

A Class MA Article 4 direction removes the commercial-to-residential prior approval route across the Central Activities Zone, and several conservation areas carry directions removing permitted development for front alterations. Coverage differs by area, so we check the schedule for your address before recommending any permitted development route.

Checked 15 Sept 2026

Great Estates and freeholder consent

Much of Westminster's housing sits on the Grosvenor, Portman, Howard de Walden, Crown and Church Commissioners estates, whose consent is required for external and often internal alterations in addition to planning permission. Estate design guidance can be stricter than the council's.

Checked 15 Sept 2026

Thames flood zone

Pimlico, Millbank, Victoria Embankment and the riverside fall within Flood Zones 2 and 3, protected by the Thames Barrier and river walls. Basements there need a flood risk assessment and may need flood-resilient design.

Source · Checked 15 Sept 2026

What City of Westminster planning officers look for

Westminster is one of the two strictest householder planning authorities in London alongside Kensington and Chelsea. Officers expect extensions to be subordinate, to follow the established pattern on the terrace and to use matching materials; rear extensions above closet-wing height, roof extensions on terraces with unbroken rooflines and front-elevation changes are commonly refused. Basements are decided as much on construction method and neighbour impact as on design. Pre-application advice is available for a fee and we recommend it for most projects in the City.

Council links

Extensions and loft conversions in Westminster

Westminster’s housing is almost entirely nineteenth century and almost entirely designated: stucco terraces and squares in Pimlico, Belgravia and Bayswater, Georgian townhouses in Marylebone and Mayfair, the mews behind them, mansion blocks in Maida Vale and St John’s Wood, and Victorian terraces in Queen’s Park. Most homes are flats. The typical brief is a rear extension to a terrace or mews house, a mansard where the terrace pattern allows, a reworked mansion flat, or a single-storey basement.

Nearly all of it needs planning permission, much of it needs listed building consent, and a large share needs the consent of a Great Estate freeholder as well. We run the three processes together and treat pre-application advice as the norm.

Planning constraints in Westminster

The designations that shape nearly every project in the City are:

  • Conservation areas (more than 50) covering the great majority of housing, removing PD for roof extensions and most external alterations.
  • The basement Article 4 direction and City Plan basement policy, limiting basements to a single storey and half the garden with full technical information.
  • Listed buildings, more than in any other London borough.
  • Class MA and conservation-area Article 4 directions across the Central Activities Zone.
  • Great Estate freeholders whose consent is needed in addition to planning.
  • Flood Zones 2 and 3 along the Thames at Pimlico and Millbank.

We check tenure, listing, conservation area, Article 4 and estate status for your address before we quote so the route is clear from day one.

What Westminster planning officers look for

Westminster’s officers expect extensions to be subordinate and to follow the established pattern on the terrace. Rear extensions should not rise above closet-wing height or project beyond neighbouring precedent, and should use matching stucco, brick and sash detailing. Roof extensions are judged terrace by terrace: a mansard behind a parapet may be supported where the terrace already has them, but breaking an unbroken roofline is usually refused. Front dormers and front-elevation changes are rarely accepted.

For basements they look closely at structural method, groundwater, drainage and construction management alongside depth and garden take. For listed buildings they expect a heritage statement that justifies every intervention. Pre-application advice is available for a fee and we recommend it for most projects.

Our services in Westminster

Example projects nearby

Guides

Read our guides on extending or converting a loft in a conservation area and householder planning applications in London.

Ready to start in Westminster? Get an instant estimate: your indicative fee on screen and by email in two minutes, then a written fixed-fee quote within 24 hours.

04Examples

Example projects in and around Westminster

Proposed ground floor plan of a wraparound side-return and rear extension to a Victorian terrace in Kentish TownExample project
Wraparound extensionKentish Town, Camden

Wraparound Extension in Kentish Town, Camden

Side-return infill and 3 m rear extension forming a wraparound kitchen-dining room on a Victorian terrace in a Kentish Town conservation area, with steelwork bearing on both party walls.

Typical route: Pre-application advice, then a householder planning application

05Questions

Planning questions we hear in Westminster

Are there Article 4 directions in Westminster?

Yes. A borough-wide Article 4 direction removes permitted development for basement excavations, a Class MA Article 4 removes the commercial-to-residential prior approval route across the Central Activities Zone, and several conservation areas carry directions removing rights for front alterations. The exact coverage varies by area, so we check the schedule for your address at the outset.

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

Almost always. Most homes in Westminster are flats, which have no permitted development rights, and nearly every house sits in a conservation area where Article 4 directions apply. Even where a single-storey rear extension is technically permitted development, we usually recommend a planning application or a Lawful Development Certificate so there is no doubt on sale.

Can I dig a basement under my Westminster house?

Possibly, but under strict rules. The City Plan limits new basements to a single storey beneath the house and no more than half the garden, and asks for structural, drainage and construction management information. Every basement needs planning permission because of the Article 4 direction, and Great Estate consent where applicable. We coordinate the engineer's input so the application is complete on submission.

How long does Westminster council take to decide a householder application?

The statutory period is 8 weeks from validation for a householder application or a Lawful Development Certificate, and 8 weeks for listed building consent. Westminster handles one of the highest volumes of heritage applications in the country and often uses the full period or agrees an extension of time. The council fee is £528 for a householder application (verify before applying).

What is Great Estate consent and do I need it?

If your home is on the Grosvenor, Portman, Howard de Walden, Crown or Church Commissioners estates, the freeholder's consent is needed for external and often internal alterations, separately from planning permission and listed building consent. Estate design guidance can be stricter than the council's. We check the title at the outset and prepare drawings that satisfy both processes.

06Coverage

Everywhere we work

One team, one process, every area. Choose yours.

Central

North

East

South

West

Next step

Planning a project in Westminster?

Answer six questions and your indicative fee for Westminster arrives on screen and by email in two minutes, with a written fixed-fee quote within 24 hours.

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