Hampstead Architecture and Planning

Kensington & Chelsea

Architects in Kensington

We design and prepare drawings for Kensington townhouses, mansion flats and terraces, navigating RBKC planning, conservation and basement policy.

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The short answer

Is Kensington a conservation area?

Much of Kensington sits within the Kensington Conservation Area, whose appraisal the Royal Borough of Kensington and Chelsea adopted on 3 February 2017. RBKC also maps separate designations across the wider area, including Kensington Court, Kensington Palace and Kensington Square, so the first step is confirming which conservation area, if any, covers your exact address before relying on any appraisal.

Planning at a glance

Kensington

Planning at a glance in Kensington
Local planning authorityRoyal Borough of Kensington and Chelsea
Conservation areaKensington Conservation Area (where mapped; other RBKC conservation areas may apply) — appraisal adopted 3 February 2017 (Kensington Conservation Area appraisal only)
Likely approval routeHouseholder planning application or permitted development, depending on conservation status, listing and property type — confirmed for the exact address before drawings begin
Statutory determination time8 weeks for most householder applications (13 weeks for major applications)
Local planning noteRBKC maps distinct conservation areas across the wider Kensington area, including Kensington, Kensington Court, Kensington Palace and Kensington Square. Confirm the exact address before selecting an appraisal or assuming conservation-area status.
Where most projects startPlanning Route Review — £395 inc. VAT, credited in full against your package if you proceed. Find my package →

Kensington is one of London’s grandest residential districts, with stucco-fronted townhouses, garden squares, mansion blocks and period terraces. It lies within the Royal Borough of Kensington and Chelsea, an authority known for rigorous planning and conservation policies and for specific, well-developed basement controls. Design expectations are high, and proposals are assessed with care, so a credible, well-presented case matters.

The projects we see most in Kensington are basement and lower-ground works to add space on constrained plots, comprehensive refurbishment of townhouses, the reconfiguration of mansion flats, and carefully designed rear extensions. RBKC’s basement policy limits the depth and extent of below-ground development and requires supporting reports, so basement feasibility must be assessed against that policy from the outset. Where buildings are listed — and many are — internal as well as external alterations can require consent.

Because Kensington sits within RBKC, proposals are assessed against the borough’s local plan, conservation-area appraisals, basement policy and the listing of the building. We design to those exacting standards, coordinate the structural, waterproofing, heritage and party wall input prime Kensington projects require, and prepare the planning, listed building consent and building regulations drawings needed — while being clear that no planning outcome can be guaranteed. As conservation area architects in Kensington and Chelsea, we frame each application against the specific appraisal that covers the address rather than a generic borough summary.

Local analysis

What matters in Kensington

Property types and street grain in Kensington

Kensington work can involve large terraces, garden-square houses, mansion flats, converted buildings, mews properties and apartments close to Kensington High Street, where RBKC conservation and leasehold routes are often decisive.

Planning authority and boundaries in Kensington

The address should be checked against the RBKC conservation area list, Kensington appraisal, listed-building records, Article 4 directions, garden-square rules and freeholder or estate controls.

Who reviews a Kensington project

A Kensington package may need to answer RBKC planning, conservation officers, estate or garden-square reviewers, freeholders, managing agents, building control, consultants and the contractor.

Technical constraints in Kensington

Kensington flats and terraces can be constrained by heritage interiors, acoustic floors, risers, fire separation, vaults, basements, lightwells, roof terraces, plant and common-part protection.

Construction and access in Kensington

Construction planning should cover high-management buildings, delivery limits, scaffolding, neighbour protection, common-part routes, services shutdowns and careful sequencing around retained fabric.

Sequencing consents on a Kensington project

Few Kensington projects answer to a single approval. A house in a conservation area may need planning permission and, where the building is listed, listed building consent, which can reach interior alterations as well as the elevations; a mansion flat usually adds a freeholder's Licence to Alter; garden-square or estate reviewers may sit alongside the council; and party wall procedures under the Party Wall etc. Act run separately from all of them. Treating these as one queue causes most of the delay we see, because each route has its own information demands and its own clock.

A workable order starts with the address checks, establishing which RBKC conservation area applies, whether the building is listed and whether an Article 4 direction covers the street, followed by a measured survey, since every later drawing depends on it. A householder application carries a statutory target of around eight weeks once validated, but that clock only starts when the submission is complete, and basement proposals should not be lodged until the supporting reports RBKC's policy expects are assembled. Pre-application advice can be worth the extra stage on sensitive or listed addresses, and building regulations can then follow as full plans for certainty or a building notice where the work is simple, which in Kensington it rarely is.

What a Kensington drawing set has to prove

The drawing set for a Kensington application has to do more work than a standard suburban package. Because RBKC assesses proposals against conservation-area appraisals and, where relevant, the listing of the building, the existing drawings matter as much as the proposed: a measured survey should record the fabric the appraisal cares about, including elevational detail and, for houses, vaults, lightwells and the roofscape, so officers can see precisely what changes. Where an Article 4 direction applies, RBKC's guidance names windows, front doors, boundary walls and roof coverings as examples of controlled external changes, so those elements deserve drawn detail rather than a passing note.

It also helps to keep the three tiers of information distinct. Planning and listed building drawings argue the case for consent; building regulations drawings, whether submitted as full plans, which gives a checked approval before work starts, or under a building notice, demonstrate compliance; and contractor information prices and builds the job. For a mansion flat, a parallel package usually goes to the freeholder or managing agent for the Licence to Alter, often with acoustic, fire and services evidence the council never sees. Preparing these as one coordinated set, rather than redrawing at each stage, is where an experienced hand saves a Kensington programme the most time.

Local services

How we would approach projects in Kensington

Choosing an architectural service in Kensington

Kensington advice should identify the RBKC designation, garden-square or estate route, listed status and technical constraints before the service is priced.

For apartments, the useful package should distinguish interior design, Licence to Alter, building control, acoustic evidence and contractor information.

Local evidence

What the local evidence tells us about Kensington

Where local advice starts in Kensington

RBKC lists the Kensington Conservation Area Appraisal as adopted on 3 February 2017 and identifies Kensington as one of the borough’s major conservation contexts, with nearby palace, square and garden-square designations.

Official signals for Kensington

Royal Borough of Kensington and Chelsea.

Kensington Conservation Area.

garden squares.

Kensington Palace Conservation Area.

RBKC Article 4 controls.

Verified local facts for Kensington

RBKC lists the Kensington Conservation Area Appraisal with an adoption date of 3 February 2017.

RBKC lists Kensington Palace Conservation Area Appraisal with an adoption date of 17 July 2025.

RBKC lists Kensington Square Conservation Area Appraisal with an adoption date of 23 November 2017.

RBKC Article 4 guidance identifies windows, front doors, boundary walls and roof coverings as examples of controlled external changes in conservation areas.

Official sources to check for Kensington

Check RBKC Kensington, Kensington Palace, Kensington Square, De Vere, Courtfield and nearby conservation records as applicable.

Check Article 4 directions, listed-building entries, garden-square or estate rules and lease/freeholder requirements.

Check planning history, vaults, basements, roofscape, acoustic floors, fire separation, risers and common parts before tender.

Planning record for Kensington

Kensington Conservation Area (where mapped; other RBKC conservation areas may apply). RBKC maps distinct conservation areas across the wider Kensington area, including Kensington, Kensington Court, Kensington Palace and Kensington Square. Confirm the exact address before selecting an appraisal or assuming conservation-area status. Recorded 3 February 2017 (Kensington Conservation Area appraisal only).

Local process

How we would sequence a project in Kensington

Questions to answer before design in Kensington

Is the property in Kensington, Kensington Palace, Kensington Square, De Vere, Courtfield or another RBKC conservation area?

Does a garden-square, estate, freeholder or managing-agent rule control the proposed works?

Do listed fabric, acoustic floors, vaults, basements, roof terraces, plant or common parts change the scope?

Documents for an initial Kensington review

RBKC Kensington conservation-area appraisal, map and Article 4 check.

listed-building record, garden-square or estate rules, lease and freeholder requirements.

planning history, survey drawings, photographs of elevations, common parts, vaults, basements and roof areas.

Thinking about a project in Kensington?

Send the address and a short description. We will confirm the likely approval route and the drawings your project needs.

Local planning

Planning & conservation context

Kensington lies within the Royal Borough of Kensington and Chelsea, which applies notably rigorous planning and conservation policies, including specific basement controls.

Conservation-area coverage is extensive and listing is common.

Kensington’s stucco townhouses and garden squares are closely protected, with high expectations of design quality.

Many Kensington buildings are listed, requiring listed building consent for a wide range of alterations.

For the wider local-authority picture — policies, timescales and application routes — see planning in Kensington & Chelsea.

Illustrative study — street elevation

Architecture in Kensington: FAQs

Can I build a basement in Kensington?

Basements can be possible but are subject to RBKC’s specific basement policy, which limits depth and extent and requires supporting reports, as well as ground conditions and party wall processes. We assess feasibility against the policy.

Is RBKC stricter than other boroughs for Kensington projects?

RBKC is known for rigorous planning and conservation policies and detailed basement controls. Proposals are assessed carefully, so a well-prepared, policy-aware application is important.

Are Kensington buildings often listed?

Many are. Listing must be confirmed per address and affects what internal and external alterations require consent. We check this as part of our review.

Does a Kensington flat need permission for internal reconfiguration?

Usually the planning question is the smaller one. Internal alterations to an unlisted flat generally fall outside planning control, so the binding routes are the Licence to Alter your lease requires and the managing agent’s conditions. Where the building is listed, internal work affecting its character needs listed building consent regardless of tenure, so confirm the listing first.

Can windows be replaced in a Kensington conservation area?

It depends on listing and tenure as much as designation. On a listed building, replacing windows requires listed building consent. Flats hold no householder permitted development rights in any case, so the lease governs, and where the external appearance changes planning permission is engaged. On these elevations, repairing original joinery is frequently both the better technical answer and the simpler consent route.

Will I need a heritage statement in Kensington?

Where the proposal affects a listed building, or a building that contributes to a conservation area, expect to provide one. It should be proportionate to the asset and the change: identifying what is significant about the building, what the proposal would affect, and why. A statement provides evidence and a reasoned view; the council determines the category of effect and the weight it carries.

How long does an RBKC decision usually take?

A householder application has a statutory target, but the realistic programme depends on validation, consultation, any request for further information and whether listed building consent runs alongside. Basement proposals and heritage-sensitive schemes attract more scrutiny and more consultation. Treat the target as a starting point rather than a completion date.

Do trees affect a Kensington project?

They can, through a route separate from the planning application. Works to a tree protected by a preservation order need the council’s consent, and works to most trees in a conservation area require six weeks’ written notice before starting. Where a tree sits close to proposed foundations its species, mature height and distance also govern the foundation design.

Discuss a project in Kensington

Tell us about your Kensington property and plans. We will advise on the RBKC planning, conservation, basement and listing position and the drawings required.

Call 020 8054 8756Send Details