House
extensions
in Hampstead Heath, NW3
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 Hampstead Heath house extensions across South End Road, Willow Road, Tanza Road - side-return, rear, wraparound and double-storey additions for Heath-Adjacent Victorian villas, Edwardian terraces and larger family homes where planning strategy, conservation detailing, Party Wall sequencing and structural engineering need handling properly.
House Extensions in Hampstead Heath: What You Need to Know
Every house extension project in Hampstead Heath is designed to respect the Hampstead Conservation Area and the character of Heath-adjacent Victorian villas, Edwardian terraces, Heath-facing mansion flats. Our in-house RIBA Chartered Architects handle Camden 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.
Hampstead Heath's conservation area status means extensions must be sensitively designed. Camden expects extensions to use matching or complementary materials and to respect the scale and character of the original building. We navigate these requirements daily.
Properties directly adjoining Hampstead Heath command London's highest premiums. Combination of Hampstead and Highgate conservation areas with the most sensitive planning environment in north London. Side-return extensions are particularly popular in Hampstead Heath's terraced streets, transforming narrow kitchen spaces into full-width open-plan living areas connected to the garden.
Extending a house near Hampstead Heath is, before anything else, about the Heath itself. The relationship with the open landscape makes context, outlook and historic fabric central to the brief, across the flats and period houses around South End Road and Parliament Hill in NW3.
The consent framework reflects that sensitivity. The local heritage set covers conservation areas, listed buildings in NW3, roof developments and rear extensions, with Licences to Alter for NW3 flats — so a rear addition is designed for its setting and its consents from the outset rather than treated as a standard back-of-house job.
On budget, the Camden measure puts a single-storey rear extension at £71,250–£112,500 excluding VAT, a side return at £90,000–£120,000 excluding VAT and a wraparound at an indicative £100,000–£200,000; a survey and the consent route then narrow those bands to your house.
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 Hampstead Heath: Questions
What makes extending near Hampstead Heath distinctive?
The Heath itself. Its relationship with the open landscape makes context, outlook and historic fabric central to the brief, across the flats and period houses around South End Road and Parliament Hill, so an extension is designed to sit within that setting.
What consents apply to a Hampstead Heath extension?
The NW3 heritage set covers conservation areas, listed buildings, roof developments and rear extensions, with Licences to Alter for NW3 flats, so the consent route is confirmed before the design is fixed.
What does a house extension cost near Hampstead Heath?
In Camden a single-storey rear extension comes to £71,250–£112,500 excluding VAT, a side return to £90,000–£120,000 excluding VAT, and a wraparound to an indicative market band of £100,000–£200,000.
How is a kitchen extension near Hampstead Heath priced?
Around £2,200–£3,500 per square metre of new floor area, plus a £5,000–£30,000 kitchen supply allowance, the build rate excluding VAT. The size and specification then set the scheme figure.
Which Hampstead Heath streets do you work on?
The flats and period houses around South End Road and Parliament Hill, where the Heath frames the outlook and the setting is as much part of the brief as the building itself.
How much does a house extension cost in Hampstead Heath, NW3?
House extensions in Hampstead Heath typically cost £3,200–£5,500/sqm. A single-storey rear extension runs approximately £69,000–£115,000, while a double-storey extension costs £115,000–£207,000. Our fixed-price contracts include foundations, structural steelwork, full build and interior fit-out.
House Extensions in Hampstead Heath: Planning & Local Context
London Borough of Camden · NW3
Planning for house extensions in Hampstead Heath
Rear and side-return extensions are popular in Hampstead Heath, but permitted-development rights are frequently restricted within the Hampstead and Highgate conservation areas around the Heath, so most extensions need a full planning application to London Borough of Camden with design that respects the prevailing building line and materials.
London Borough of Camden & Hampstead and Highgate conservation areas around the Heath context
Hampstead Heath NW3 sits within the Hampstead and Highgate conservation areas around the Heath, and Camden enforces Article 4 directions across its conservation areas (removing many permitted-development rights) and applies its CPG basement guidance to subterranean work. Heath-edge sites also engage City of London open-space protections. Our in-house RIBA Chartered Architects prepare and submit every application to London Borough of Camden and handle pre-application discussions where early planning advice is useful.
Building Regulations
House Extensions in Hampstead Heath must satisfy Building Regulations — covering structural design to Part A, thermal performance to Part L, and drainage and foundations agreed with Building Control. Our in-house engineers manage Building Control from initial notice through to the completion certificate.
Recent work & local links
Explore our other Hampstead Heath services — Kitchen Renovation Loft Conversions — or the Hampstead Heath renovation hub for the full picture of how we work locally.
Our in-house planning team prepares and submits every London Borough of Camden application and manages building control end to end. View our planning track record →
More Services in Hampstead Heath
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We survey your property, discuss your vision and provide a clear budget framework.