House
extensions
in Bayswater, W2
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 Bayswater house extensions across Gloucester Terrace, Westbourne Terrace, Leinster Gardens - side-return, rear, wraparound and double-storey additions for Stucco Italianate terraces, Garden-Square houses and larger family homes where planning strategy, conservation detailing, Party Wall sequencing and structural engineering need handling properly.
House Extensions in Bayswater: What You Need to Know
Every house extension project in Bayswater is designed to respect the Bayswater Conservation Area and the character of stucco Italianate terraces, garden-square houses, large mansion flats. Our in-house RIBA Chartered Architects handle 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 Bayswater's conservation area, extensions must be designed with exceptional sensitivity. Westminster 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.
Wide tree-lined avenues with grand white stucco terraces overlooking garden squares. Westminster conservation area. Many properties converted to flats requiring sensitive renovation. Our extensions in Bayswater use materials and detailing that complement the existing architecture — whether matching traditional brickwork and stonework or introducing high-quality contemporary glazing and zinc cladding.
Bayswater is grand stucco north of the park, and an extension is designed to keep those frontages reading as a single run. The area lies in the City of Westminster, inside the Bayswater Conservation Area, along the great stuccoed streets facing Kensington Gardens. Westbourne Terrace and Gloucester Terrace hold monumental white-fronted runs, and value across W2 rests on consistent street lines, room proportions and original joinery — so external change is judged against the coherence of the terrace.
The stock leans large and often leasehold. Leinster Gardens and Queensborough Terrace offer substantial garden-square houses suited to whole-house refurbishment and reconfiguration, while much of the wider stock is now mansion flats. Bayswater's heritage material covers conservation areas, facade rules, roof developments, listed buildings and Licences to Alter for W2 flats, so a converted house is worked up for both the planning decision and the freeholder's consent.
Cost tracks that complexity rather than plan area. A Bayswater rear extension is broadly £71,250 to £112,500 before VAT; a side return runs to £90,000 to £120,000, and a wraparound shows as an indicative £100,000 to £200,000 market band.
House Extensions in Bayswater: Applied to the Local Stock
Bayswater sits in the City of Westminster, within the Bayswater Conservation Area, on the great stuccoed streets north of Kensington Gardens. London-wide indicative market band for wraparound extension: £100,000–£200,000 (source VAT treatment unstated, shown as an indicative market band, not a normalised ex-VAT figure) (Resi wraparound extension guide, 2025).
Sources: Westminster City Council — Bayswater Conservation Area mini guide (Oct 2004) (2026); Wraparound extension (Resi wraparound extension guide, 2025) (2026)
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 Bayswater: Questions
How does the Bayswater Conservation Area affect extensions?
Bayswater lies in the City of Westminster, inside the Bayswater Conservation Area, along the great stuccoed streets north of Kensington Gardens. Because value here rests on consistent street lines and the interplay of houses, flats and mature settings, external change is judged closely and stucco frontages are kept whole.
Which Bayswater streets have the grand houses suited to extending?
The stucco Italianate terraces and garden-square houses. Westbourne Terrace and Gloucester Terrace hold monumental white-fronted runs, while Leinster Gardens and Queensborough Terrace offer substantial period houses well suited to whole-house refurbishment and reconfiguration. Those larger houses are the natural candidates for ambitious W2 work.
What does an extension cost in Bayswater?
London-wide guidance places a Bayswater rear extension broadly at £71,250 to £112,500 before VAT. Reckon on £90,000 to £120,000 for a side return and an indicative £100,000 to £200,000 for a wraparound. Where a house has been split into flats, the leasehold consents and coordination weigh on the figure alongside the works.
Do leasehold flats complicate extending in Bayswater?
Frequently. Bayswater's heritage material addresses conservation areas, facade rules, roof developments, listed buildings in W2 and Licences to Alter for W2 flats. Where a house has been converted, a Licence to Alter runs alongside Westminster's decisions, so an addition or internal change is designed for both consent routes.
What is the property stock like in Bayswater?
W2's stock is stucco Italianate terraces, garden-square houses and large mansion flats, with value tied to consistent street lines, room proportions, original joinery and the relationship between houses, flats and mature settings. Its characteristic streets include Westbourne Terrace, Gloucester Terrace, Leinster Gardens and Queensborough Terrace.
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We survey your property, discuss your vision and provide a clear budget framework.