Why Hampstead homeowners choose extensions
Hampstead properties are among London's most valuable — but many original layouts are compact by modern standards. A house extension in Hampstead opens up the ground floor for contemporary open-plan living, adds a proper family kitchen, creates a seamless indoor-outdoor connection, or provides an extra reception room — all without the enormous cost and disruption of moving.
In Hampstead and Hampstead Heath, a well-designed extension adds £100,000–£350,000 to your property value. Side-return extensions on Victorian terraces are particularly effective, transforming narrow galley kitchens into spacious kitchen-diners flooded with natural light.
We've built extensions on Victorian terraces near the Heath, Edwardian semis on Fitzjohn's Avenue, period cottages in Hampstead Village, and listed properties in the conservation area. We know Camden Council's planning policies inside out — including what you can build under permitted development and what needs a full application.
Why extensions in Hampstead require specialists
Hampstead's unique character means house extensions here need expert local knowledge. Here's why.
Conservation Area Design
Much of Hampstead is a conservation area. Extensions must be sympathetic to the existing architecture — materials, proportions and detailing all matter. We design extensions that conservation officers approve.
Permitted Development Rules
Many single-storey rear extensions can be built under PD without a planning application. But conservation area restrictions and Article 4 directions can change the rules. We check your specific property before designing.
Party Wall Management
Side-return and rear extensions on terraced properties require party wall agreements with neighbours. We serve notices, appoint surveyors, and manage the entire process — included in our price.
Structural Complexity
Victorian and Edwardian properties need careful structural design — removing loadbearing walls, installing steel beams, underpinning foundations. Our in-house structural engineer handles all calculations.
Proximity to Hampstead Heath
Properties near the Heath may face tree preservation orders, ecological surveys, and increased planning scrutiny. We handle all environmental and heritage requirements.
Premium Return on Investment
With average Hampstead property values above £1.5M, an extension adds proportionally more value here than almost anywhere in London. A £70,000 extension can add £200,000+ in value.
"Hampstead Renovations transformed our cramped Victorian kitchen into a stunning open-plan kitchen-diner with bi-fold doors to the garden. The team managed all the planning and party wall issues, and the quality of the build was outstanding."Sarah & David MitchellHomeowners, Hampstead NW3
House extension costs in Hampstead
Realistic prices from recent Hampstead projects. We provide a fixed, all-inclusive quote after a site survey.
| Extension Type | Typical Range (Hampstead) |
|---|---|
| Single-storey rear extension | £55,000 – £90,000 |
| Side-return extension | £45,000 – £70,000 |
| Wrap-around (rear + side) | £80,000 – £130,000 |
| Two-storey rear extension | £100,000 – £170,000 |
| Kitchen extension (open-plan) | £60,000 – £100,000 |
| Glass box / frameless glazing | £70,000 – £130,000 |
| Orangery-style extension | £65,000 – £110,000 |
| Bi-fold / sliding doors | £3,500 – £8,000 |
| Underfloor heating | £2,500 – £5,000 |
All prices exclude VAT. Includes foundations, structural steelwork, brickwork, roofing, windows, electrics, plumbing, plastering, decoration and Building Control sign-off. Prices reflect Hampstead-area build costs as of 2026.
House extension FAQ — Hampstead
Many single-storey rear extensions up to 3m (terraced) or 4m (detached) fall under Permitted Development. However, Hampstead conservation area rules often restrict PD rights. Side-return and two-storey extensions usually need planning. We check your specific property.
A single-storey rear extension typically takes 10–14 weeks. Wrap-around extensions 14–18 weeks. Two-storey extensions 16–22 weeks. Add 4–8 weeks beforehand for design, structural engineering and party wall, plus 8 weeks if planning permission is needed.
A single-storey rear extension in Hampstead runs £55,000–£90,000. Side-returns £45,000–£70,000. Wrap-around £80,000–£130,000. Two-storey £100,000–£170,000. All prices are all-inclusive with no hidden extras.
Almost certainly. Victorian terraces are excellent candidates for side-return and rear extensions. We've extended hundreds of terraces across NW3. The key is getting the design right for the conservation area and managing party walls with neighbours.
We manage all party wall agreements and neighbourly relations. We keep noise to minimum hours, maintain clean sites, and communicate proactively with adjoining owners throughout the build. Good neighbour relations are part of our service.
Yes — this is the most popular extension type in Hampstead. We remove the rear wall, install a structural steel beam, and extend out to create a large open-plan kitchen-diner with bi-fold or sliding doors to the garden. It transforms the way you use the house.
Book a free extension consultation in Hampstead
We'll visit your Hampstead property, assess extension options, check planning constraints, and give you a realistic price — completely free, no obligation.
Unit 3, Palace Court, 250 Finchley Road, Hampstead, London NW3 6DN
Mon–Fri 9am–8pm · Saturday 9am–6pm · Sunday by appointment
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