House
extensions
in Fitzrovia, W1T
Architects, Engineers, Surveyors & Builders Under One Roof.
One Studio. One Contract. One Team.
RICS surveying support for party walls, licence to alter, conservation-area works & neighbour mattersWe design and build Fitzrovia house extensions across Charlotte Street, Fitzroy Square, Goodge Street - side-return, rear, wraparound and double-storey additions for Georgian townhouses, Regency terraces and larger family homes where planning strategy, conservation detailing, Party Wall sequencing and structural engineering need handling properly.
House Extensions in Fitzrovia: What You Need to Know
Every house extension project in Fitzrovia is designed to respect the Fitzroy Square Conservation Area and the character of Georgian townhouses, Regency terraces, mansion flats. Our in-house RIBA Chartered Architects handle Camden, Westminster planning applications, our chartered structural engineers specify any load-bearing work, and our directly-employed trades deliver the build under one fixed-price contract. We coordinate Building Control, Party Wall awards where needed, and all certifications through to handover.
In Fitzrovia's conservation area, extensions must be designed with exceptional sensitivity. Camden officers assess impact on the host building, neighbouring properties, and the wider streetscape. We secure planning approval through design excellence and thorough pre-application engagement.
Creative quarter between Bloomsbury and Marylebone with Georgian townhouses, media offices, and characterful streets. Split between Camden and Westminster boroughs. Our extensions in Fitzrovia use materials and detailing that complement the existing architecture — whether matching traditional brickwork and stonework or introducing high-quality contemporary glazing and zinc cladding.
Fitzrovia is one of central London's best-kept secrets, and it carries an administrative quirk that shapes every extension: the neighbourhood straddles the City of Westminster and the boundary with Camden. Both authorities' controls can apply at the edges, so establishing which council governs the address early keeps a scheme on track. The Fitzroy Square Conservation Area protects the finest streets, and conservation scrutiny is close throughout.
The stock is handsome and tightly packed. Fitzroy Square is a Robert Adam set-piece of fine Georgian houses; Charlotte Street and Goodge Street blend period townhouses with flats above the restaurants; and Warren Street and the surrounding blocks add mansion flats and conversions. Across W1 the mix runs from Victorian terraces and Georgian townhouses to mews properties, so each project is set out for its particular building type.
Access defines the build, and the budget with it. A Fitzrovia rear extension typically reaches £71,250 to £112,500 before VAT, a side return £90,000 to £120,000, with demanding deliveries around Charlotte Street adding to both.
What a House Extension Involves
An extension reshapes how the whole ground floor works, not just how big it is — the new structure, the opening into the existing house, the kitchen and the garden connection all have to be designed as one move. We take each project from feasibility drawings through consents, structure and fit-out under a single fixed-price contract. Most extensions we build include the scope below.
- Rear extensions — single-storey additions that open the back of the house to the garden
- Side-return & wraparound — infilling the side alley of a terrace, alone or combined with a rear addition
- Double-storey — new bedrooms or bathrooms above the ground-floor addition, designed to sit comfortably with the original roofline
- Foundations & steel — groundworks, beams and the opening into the existing house, engineered by our own structural team
- Glazing — rooflights, glazed roofs and slim-framed sliding or bi-fold doors specified for light and thermal performance
- Kitchen integration — the kitchen layout planned with the architecture from the first drawing, not squeezed in afterwards
- Services & heating — electrics, plumbing, drainage and underfloor heating built into the new floor
- External works — patio, drainage connections and garden reinstatement completed within the contract
How We Run Your Project
Six stages, with the consents and engineering settled before the first spade goes in.
- Feasibility visit — we assess the site, the boundaries and your brief, and identify the right consent route for your property.
- Design & approvals — our architects draw the scheme while planning or permitted development paperwork, structural calculations and party wall notices progress together.
- Fixed-price contract — every element specified and priced before construction, from foundations to door hardware.
- Groundworks & shell — excavation, foundations, walls, steel and roof, taken to weathertight while you carry on living in the house.
- Fit-out — insulation, services, glazing, kitchen, flooring and decoration, with the opening into the existing house formed once the shell is sealed.
- Completion — building control inspection, snagging, external works and handover with the full certification pack.
Read the full house extension guide for extension types, permitted development limits and the build programme stage by stage.
Many rear extensions can proceed under permitted development — broadly up to 3m deep on attached houses and 4m on detached, extendable to 6m and 8m through the prior approval scheme — but conservation areas, Article 4 directions and listed status change the picture, and every extension needs Building Regulations approval regardless of the planning route. Where foundations come within 3m of a neighbouring building, the Party Wall etc. Act 1996 obliges you to give adjoining owners a minimum of two months’ written notice before construction can begin. Our planning guide library sets out the rules for each borough.
Why Hampstead Renovations
We hold £10 million public liability insurance with Aviva; the certificate is available on request.
House Extensions in Fitzrovia: Questions
Which council decides my extension in Fitzrovia, Westminster or Camden?
That is the first thing to pin down. Fitzrovia straddles the City of Westminster and the boundary with Camden, and both authorities' controls can apply at the edges. We establish which one governs at the outset, because the answer changes the process for a Fitzrovia extension before any design begins.
How does the Fitzroy Square Conservation Area affect extensions?
It protects the finest streets. The Fitzroy Square Conservation Area takes in the Robert Adam set-piece of fine Georgian houses and the blocks around it, conservation scrutiny is close, and access on the narrow streets is tight. So a proposal near Fitzroy Square is judged against a distinguished and carefully guarded townscape.
What does an extension cost in Fitzrovia?
London-wide guidance has a Fitzrovia rear extension reaching £71,250 to £112,500 before VAT. A side return typically exceeds that, at £90,000 to £120,000, with a wraparound at an indicative £100,000 to £200,000. On the narrow streets the tight access and close conservation scrutiny influence the figure alongside the added floor area.
What kind of buildings does Fitzrovia offer for extending?
Fitzrovia's stock is Georgian townhouses, Regency terraces and mansion flats. Fitzroy Square is a Robert Adam set-piece of fine Georgian houses, Charlotte Street and Goodge Street blend period townhouses with flats above the restaurants, and Warren Street and the blocks around it add mansion flats and conversions.
Why does access matter so much for Fitzrovia projects?
W1 here combines Victorian terraces, mansion flats, mews properties and mixed residential streets around Charlotte Street, Goodge Street, Great Titchfield Street and Fitzroy Square. On that tight grid, access is demanding and conservation scrutiny is close, so deliveries and site set-up are planned carefully into any Fitzrovia extension programme.
House Extensions in Nearby Areas
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We survey your property, discuss your vision and provide a clear budget framework.