Builders in Marylebone, W1

Why Building in Hampstead NW3 Is Different

Our studio sits at Unit 3, Palace Court, 250 Finchley Road, NW3 6DN — a short walk from Hampstead village, Belsize Park and Frognal. Operating a builder in Hampstead from Portsmouth or Essex is a fundamentally different proposition to operating one where the team knows every conservation sub-area, every Camden case officer and every reclamation yard that supplies the right London stock brick. We are local, permanent and accountable on the same street as our projects.

Unlike most firms calling themselves "builders in Hampstead" — who are essentially sole-trader contractors subcontracting design, planning and structural work to third parties — we are an integrated design-build practice. Our RIBA chartered architects, RICS regulated surveyors, IStructE chartered engineers and FMB-registered site teams are all directly employed, not bought in per project. That means a single contract, a single insurer, a single point of responsibility, and no finger-pointing between separate firms when a detail needs resolving on site.

Hampstead's built fabric — Georgian terraces along Church Row, Victorian villas on Frognal Lane, Edwardian mansion blocks around Flask Walk and Well Walk, and the rare listed houses off Downshire Hill — demands methodology that a general builder is not equipped for. We work daily with lime mortar rather than cement, match reclaimed London stock brick rather than standard commons, commission period-correct sash windows with 20mm astragals rather than off-the-shelf replacements, and retain specialist sub-trades for sash window restoration, lime plastering, cornice moulding and cast-iron repair. Camden's Hampstead Conservation Area Appraisal and its various Article 4 directions are not obstacles we learn on your project — they are the policy environment we work in every week.

Hampstead NW3 Building Considerations

Camden · NW3

Camden Article 4 directions

Large portions of Hampstead sit under Camden Article 4 directions that remove permitted development rights homeowners elsewhere take for granted — cladding, window replacement, front porches, roof alterations and most front-facing external changes now require a full householder application. Within the Hampstead Conservation Area itself, the Article 4 regime is materially more restrictive than standard Camden policy, and a quick "just-swap-the-windows" project often becomes a planning submission with heritage statement attached. We check Article 4 status for every NW3 postcode at feasibility stage, before any drawings are commissioned.

Conservation area materials policy

Camden's conservation team will reject schemes that specify standard modern materials in Hampstead. Brickwork must be London stock, laid in NHL lime mortar with a flush weatherstruck joint — not cement. Windows must be timber sash with slim 20mm astragals and historically appropriate glazing bar arrangements. Roofs must be natural slate or clay tile, never concrete. We hold long-standing accounts with reclamation yards for stock brick and commission joinery from workshops that make period-accurate sashes, casements and door frames to drawing — not from catalogues.

Party wall and neighbour impact

Hampstead's tightly-packed Victorian terraces and joined mansion flats mean almost every build in NW3 triggers Party Wall Act 1996 notifications — sections 1, 2 and 6 in most cases, and increasingly serial section 6 notices to adjoining owners above and below when working in the lower ground. Our in-house RICS surveyors draft notices, conduct schedules of condition and negotiate the award without going to the additional expense of instructing a third-party surveyor. On congested streets like Willoughby Road or South End Road, this alone can save four to eight weeks of pre-construction time.

Building control and heritage compliance

Every Hampstead build we deliver carries NHBC or ABC+ 10-year structural warranty, full Camden Building Control sign-off against current Parts A through P, and where the property is in the Hampstead Conservation Area (or listed) we prepare the heritage statement and Design & Access Statement required by Camden's validation checklist. Listed Building Consent is a separate consent regime from planning — our applications bundle both where applicable, avoiding the common trap of receiving planning approval but being unable to lawfully start work.

Our in-house planning team has a 97% approval rate across Camden. View our planning track record →

Frequently Asked Questions About Builders in Hampstead

Camden · NW3

Most builders in Hampstead subcontract design, structural engineering and planning — leaving you managing four to six separate firms with overlapping responsibilities and gaps where things get dropped. We are one practice with every discipline in-house: RIBA chartered architects, RICS regulated surveyors, IStructE chartered engineers and FMB-registered build teams. That means one contract, one point of responsibility, one fixed price and a single professional indemnity policy. When an issue arises on site — a hidden beam, a changed specification, a neighbour request — it is resolved inside our office, without finger-pointing between separate firms with conflicting commercial interests.

Yes — all planning work is handled in-house by our chartered architects and planning consultants. Our track record in the Hampstead Conservation Area and adjoining Camden conservation areas is a 97% approval rate at first submission. For any scheme where officer judgement matters — materials, massing, heritage impact, Listed Building Consent — we run pre-application consultations with Camden's conservation and design officers before we formally submit. That upstream alignment materially reduces refusal risk and removes the most common causes of committee referral or post-submission amendment.

Everything required to deliver the building, under one contract: full architectural drawings, 3D visualisations, structural calculations and engineer sign-off, Camden planning application (and Listed Building Consent where applicable), Party Wall Act awards for all affected neighbours, Building Regulations submission and approval, the full construction scope, first and second fix, all specified finishes, and a 10-year structural warranty. No provisional sums for finishes, no day-rate labour charges, no hidden extras when the job moves onto site. The price we agree at contract is the price we invoice at handover.

Yes, and we encourage it — meeting the architects, engineers and project lead in person is the single best way to assess any builder before signing a contract. Our studio at Unit 3, Palace Court, 250 Finchley Road, NW3 6DN is open Monday–Friday, 9am–6pm, a short walk from Finchley Road & Frognal and Finchley Road tube stations. Free extension feasibility review and project scoping is available on request — we will visit your Hampstead property within the same week, assess the build, and return written scope and indicative figures before you commit to any design fee.

Marylebone W1 Design-Build Contractors

Design-Build Contracting

One practice, every discipline, one fixed price — from feasibility drawing to final handover photograph. Our RIBA architects design, our IStructE engineers calculate, our RICS surveyors handle party wall and scope, and our FMB-registered site teams deliver the build. Heritage restoration, house extensions, loft and basement conversions, full refurbishments — across Hampstead and the wider W1.

RIBA ArchitectsIn-house design & planning

IStructE EngineersIn-house structural design

Fixed-PriceFrom £2,800/sqm

Book free feasibility review View Build Portfolio

Every Build Includes

One contract, one insurer, one point of responsibility

Architectural design & 3D rendersIncluded

Structural engineering (IStructE)Included

Camden planning / LBC applicationIncluded

Building Regulations approvalIncluded

Party Wall awards (RICS)Included

Full FMB build & finishesIncluded

10-year structural warrantyIncluded

Marylebone's Design-Build Practice

Builders for How Marylebone Lives

Hampstead's housing stock is some of the most architecturally significant in London. Georgian terraces on Church Row and Well Walk, stucco Victorian villas along Frognal and Fitzjohn's Avenue, red-brick Edwardian mansion blocks around Hampstead High Street, and rare listed Arts & Crafts cottages off Downshire Hill — each property carries constraints and opportunities that a general building contractor is not equipped to navigate. The same house that earns a premium in Church Row also comes with Westminster's conservation scrutiny and Article 4 restrictions that remove most permitted development rights.

We are the design-build practice built for this. One integrated team — RIBA chartered architects, IStructE chartered engineers, RICS regulated surveyors, FMB-registered site teams — operating under one contract with one fixed price. For a typical client, the alternative is appointing four to six separate firms (architect, engineer, planning consultant, party wall surveyor, main contractor, heritage consultant), each with their own fee, their own insurer, their own schedule and their own commercial interest. That structure is where the majority of Hampstead build projects lose time and cost control.

Our scope covers the full spectrum of NW3 work: heritage restoration of listed and conservation-area fabric, rear and side-return house extensions, loft conversions (dormer, mansard and hip-to-gable, all sensitive to Hampstead roofscape policy), basement conversions and dig-downs, and full refurbishments of Georgian, Victorian, Edwardian and post-war properties. We work daily with Westminster's planning, conservation and building control teams and have a 97% first-submission approval rate across W1.

Every project starts with a free on-site feasibility review. We visit your property, assess the fabric, identify the planning route (full application, Listed Building Consent, prior approval or permitted development), check Article 4 designations for the address, flag Party Wall Act implications, and provide honest, written scope and indicative figures — before any design fees are committed.

What We Build

Four core disciplines for Hampstead NW3 properties — each priced by scope, delivered by the same integrated team, and linked below to the full service page with detailed scope and case studies.

Heritage Restoration

Conservation-area and listed-building work across Hampstead — lime mortar repointing, sash window restoration, cornice and cast-iron repair, matched reclaimed brick. Handled with Listed Building Consent and heritage statements where required.

PlanningLBC + heritage statement

Typical scopeFabric repair to full restoration

From£3,500/sqm

Heritage restoration →

House Extensions

Rear, side-return, wraparound and double-storey extensions for Hampstead's Victorian and Edwardian terraces. Kitchen-led open-plan designs with structural glazing, conservation-area-compliant materials and Camden planning managed in-house.

PlanningFull app in conservation area

Typical size15–45 sqm added

From£2,800/sqm

House extensions →

Loft & Basement Conversions

Vertical expansion: dormer, mansard and hip-to-gable loft conversions sensitive to Hampstead's roofscape policies, plus cellar conversions and basement dig-downs with full waterproofing and underpinning design by our IStructE engineers.

PlanningOften full app in NW3

Typical size25–60 sqm added

From£3,000/sqm

Loft conversions →

Full Refurbishments

Whole-house strip-out and reconfiguration — structural reordering, new services, full finishes, bespoke kitchens and bathrooms, smart home and AV. For Hampstead properties being brought into contemporary use without losing period character.

PlanningVaries by scope

Typical scopeWhole house, 120–400 sqm

From£1,800/sqm

Full refurbishment →

Planning in Camden

The Camden Planning Process for NW3 Builds

In Hampstead, permitted development is rarely available — conservation area designation and Article 4 directions see to that. Here is the real-world planning journey for a typical NW3 build, handled end-to-end by our in-house team.

From Pre-App to First Spade in the Ground

Step 1 — Pre-application consultation with Camden: For any scheme where officer judgement matters (materials, massing, heritage impact, listed fabric), we submit a paid pre-application to Camden and meet the allocated conservation or design officer on site or at their offices. Typical turnaround is 4–6 weeks. The officer's written response de-risks the main submission and flags any amendments required before we invest in the full drawing set.

Step 2 — Householder planning application (or Listed Building Consent): The main submission. We prepare the drawing pack, the Design & Access Statement, the Heritage Statement (mandatory in the Hampstead Conservation Area), CIL information and ownership certificates. Camden's statutory determination period is 8 weeks from validation. Our NW3 first-submission approval rate is 97%. Where the property is listed, Listed Building Consent runs in parallel and is submitted as a bundled application.

Step 3 — Neighbour notification and consultation: Camden posts site notices and writes to adjoining owners with a 21-day consultation period. We draft proactive letters to neighbours before submission in complex cases — a short pre-emptive conversation on Willoughby Road or Pilgrim's Lane is often worth the entire planning fee.

Step 4 — Decision at 8 weeks: Most Hampstead householder applications are decided under delegated authority by the case officer. Where a scheme is contentious — nearly always a listed building or a high-volume objection case — it goes to the Camden Planning Committee. Our pre-app work is designed to avoid committee wherever possible.

Step 5 — Building Regulations application: A separate consent regime from planning. Submitted to Camden Building Control (or an approved inspector) alongside structural calculations, SAP / Part L energy calculations, drainage strategy and fire safety design. Full Plans approval is issued before work starts.

Step 6 — Party Wall Act notices: Served at least 2 months before works commence, under sections 1, 2 and 6 of the Party Wall etc. Act 1996. In tightly-packed Hampstead terraces our in-house RICS surveyors typically need to serve on 4–8 neighbouring owners per project.

Step 7 — Build: CDM 2015 role appointed (Principal Designer and Principal Contractor both held by us on design-build schemes), site set-up, hoarding, programme confirmed with neighbours, and the build proceeds on a fixed contract.

Neighbour Management

Party Wall & Neighbour Management

In Hampstead's tightly-packed terraces and mansion blocks, the neighbour dimension is often more sensitive than the build itself. We treat it that way.

When the Party Wall Act Applies in NW3

On Hampstead's Victorian terraces — South End Road, Willoughby Road, Pilgrim's Lane — virtually every build triggers sections 1, 2 and 6 of the Party Wall etc. Act 1996. Foundations within 3m (or 6m where deeper than the neighbour's) of an adjoining wall, cutting into a party wall, or raising a party wall all require notice at least 2 months before works start. Our in-house RICS surveyors draft and serve notices, and negotiate the award, without the additional cost of a third-party surveyor — included in our contract.

Right to Light & Daylight/Sunlight

Camden assesses amenity impact under the planning system, but the common law right to light is a separate legal matter — a neighbour can seek an injunction even after planning approval if light is substantially reduced. For mansard lofts, rear extensions over 3m deep, and any work adjoining a neighbour's principal habitable rooms, we commission BRE daylight/sunlight assessments in advance. On one recent Belsize Park Gardens NW3 project this pre-empted an objection and closed the issue before Camden consultation began.

Neighbour Communication Strategy

We write to adjoining owners and leaseholders before formal Camden consultation, explaining the scheme with an A3 plan pack, answering obvious concerns, and proposing a realistic build programme. On contentious streets this materially reduces the volume and character of objections submitted during Camden's 21-day consultation — and turns neighbours who would have emailed the case officer into neighbours who stay quiet or write in support.

Site Conduct & CDM 2015

Under CDM 2015 we hold both Principal Designer and Principal Contractor duties on our design-build schemes. On narrow Hampstead streets this means scaffold licences and skip permits agreed with Camden Highways in advance, deliveries scheduled outside school drop-off, dust suppression on any brick-cutting, and a named site manager reachable by neighbours throughout the programme. It is the difference between a build the street tolerates and one the street complains about weekly.

Building Regulations

Building Regulations for NW3 Builds

A separate consent regime from Camden planning. Every build we complete carries full Building Regs sign-off and a 10-year structural warranty. Here are the Parts that matter most in Hampstead.

Part L — Energy Efficiency

The most impactful regulation for Hampstead refurbishments and extensions. New walls, roofs, floors and glazing must achieve minimum U-values: walls 0.18–0.28 W/m2K, flat roofs 0.18 W/m2K, floors 0.22 W/m2K, windows 1.4–1.6 W/m2K. Listed fabric and heritage elements carry sensitive exemptions we negotiate with Camden conservation. SAP calculations are prepared in-house.

Part B — Fire Safety

Builds within 1m of the boundary — common on Hampstead terraces — require 1-hour fire-resistant external walls and restricted openings facing the boundary. Loft conversions require protected means of escape (30-minute fire doors to the stair, mains-linked alarms). For mansard work on Victorian roofs this is designed alongside the heritage detailing, not after it.

Part E — Acoustics

Bedroom-over-bedroom conditions across party walls are the norm on Hampstead terraces. Any new wall or floor between dwellings, or forming a new bedroom against an existing party wall, must meet the Part E airborne and impact thresholds. Where we cannot meet the standard through construction alone, pre-completion sound testing is commissioned and certified.

Part M & Part P

Part M requires level thresholds and 775mm minimum door openings on new builds — occasionally at odds with the narrow corridors of original Hampstead plans, which we resolve with Camden at Full Plans stage. Part P (electrical safety) is certified by our in-house NICEIC-registered electrician, with test results bundled into handover documentation.

Warranty and insurance: Every build we deliver is covered by a 10-year structural warranty (NHBC or ABC+), £10M professional indemnity and £10M public liability, with all risks contract works insurance in place from site set-up to handover. Building Control sign-off is a condition of final invoice — we do not invoice the retention until the completion certificate is issued.

How We Build It

From First Visit to Moving In

A clear, structured process that takes the uncertainty out of extending your home.

Week 1

Free Site Visit & Feasibility

We visit your property, measure the site, assess the garden, check party wall situations and discuss your brief in detail. We identify whether your extension falls within permitted development rights or requires planning permission, and flag any conservation area, Article 4 or tree preservation order constraints. You receive a written feasibility assessment with an indicative budget and recommended approach within 48 hours.

Site survey Planning assessment Budget indication Feasibility report

Weeks 2–6

Design, Planning & Engineering

Our architects produce the extension layout with 3D visualisations. Structural engineers design the steelwork, foundations and connection details. We submit planning applications or lawful development certificates, building regulations packages and party wall notices in parallel. For design-and-build projects, the kitchen design, lighting scheme and material selections run concurrently so everything is resolved before construction starts.

Architectural drawings 3D visualisations Structural calcs Planning & party wall

Weeks 1–4 on site

Foundations & Structural Shell

Foundations are excavated and poured (typically strip or trench-fill), walls built to DPC level, floor slab laid and the structural shell erected — blockwork walls, steel beams, lintels and the roof structure. The opening between the existing house and the new extension is formed, with temporary propping supporting the existing structure until the steel beam is in position. Once the roof is weathertight, the extension is sealed and internal works begin.

Foundations Structural shell Steel beams Weathertight roof

Weeks 5–12 on site

First Fix Through to Completion

Insulation, plasterboarding, first fix electrics and plumbing, underfloor heating, window and door installation, kitchen fit-out, tiling, flooring, second fix carpentry, painting and decoration. Bi-fold or sliding doors are installed connecting the extension to the garden. External works — patio, drainage, landscaping — complete the project. Building control conducts the final inspection and issues the completion certificate.

Full interior fit-out Kitchen installation External works Building control sign-off

Extension Costs

Transparent Pricing

Guide prices for London house extensions. All prices are fixed and include design, engineering, planning, full build and decoration.

Side-Return

Terrace Favourite

£35k – £55k

Infilling the side alley with a glazed roof. Doubles kitchen width and creates a bright, open-plan ground floor. 8–15 sqm added.

Rear Extension

Most Popular

£45k – £85k

Full-width or partial rear extension with bi-fold doors to the garden. Creates a generous kitchen-diner-living space. 15–30 sqm added.

Wraparound

Maximum Ground Floor

£70k – £130k

Combined rear and side extension creating an L-shaped addition. The largest single-storey extension option. 25–45 sqm added.

Double-Storey

Space Above & Below

£80k – £160k

Two-storey extension — kitchen below, bedroom or bathroom above. Best sqm/cost ratio but requires full planning permission. 30–60 sqm total.

The Marylebone Difference

Why Our Builds Are Different

What separates a Hampstead Renovations build from a standard builder's quote.

Architect-Designed, Not Template

Every extension is designed by a RIBA architect to suit your specific house, site and lifestyle. No templates, no catalogue layouts — a bespoke design that maximises light, space and the connection between your home and garden.

In-House Everything

Architects, structural engineers, planning consultants, party wall surveyors and build teams all under one roof. No subcontracted design, no outsourced engineering, no coordination gaps between separate firms. One team, one contract, one accountable party.

Genuine Fixed-Price

The price we quote is the price you pay. Not an estimate with provisional sums. Not a price that escalates when you choose your fixtures. A fixed, agreed total covering design, engineering, the full build and every material specified in the contract.

97% Planning Success

We've secured planning approvals across every inner London borough — including conservation areas in Camden, Islington, Westminster and Haringey with the most restrictive policies.

Permitted Development Experts

We maximise what can be achieved under PD rights — including the larger home extension scheme (up to 6m rear on terraces, 8m on detached) — avoiding planning costs and delays where possible.

Glazing Specialists

Structural glass roofs, frameless glass corners, slim-profile aluminium bi-folds and floor-to-ceiling fixed glass. We design extensions that flood the ground floor with natural light.

Kitchen Integration

Most extensions are kitchen-led. Our kitchen designers work alongside the architect from day one, ensuring the kitchen layout, island position and appliance locations drive the extension geometry — not the other way round.

Party Wall Management

RICS surveyors handle all party wall notices and agreements in-house. For terraced and semi-detached extensions, party walls are always a factor — our experience streamlines the process.

Underfloor Heating

We install wet or electric underfloor heating beneath extension floors as standard on most projects — eliminating radiators and freeing up wall space in the new room.

Conservation Area Design

In sensitive settings, we design extensions that satisfy conservation officers — using appropriate materials, roof forms and detailing that complement the existing building's character.

External Works Included

Patio, drainage, garden reinstatement and boundary work are part of the fixed-price contract — not treated as extras that inflate the final bill after the extension is built.

Extension Portfolio

Recent Extension Projects

Selected house extensions completed by our team across London.

Rear

Full-Width Rear Extension

Crouch End, N8 — Victorian Terrace

6m full-width rear extension with structural glass roof and 4m bi-fold doors. Open-plan kitchen-diner with island under permitted development.

28 sqm 12 weeks PD

Wraparound

Wraparound Extension

Belsize Park, NW3 — Conservation Area

L-shaped wraparound creating 38sqm open-plan kitchen-diner with glazed side return and full-width rear doors. Planning approved in conservation area.

38 sqm 14 weeks Approved

Double-Storey

Double-Storey Rear

Muswell Hill, N10 — Edwardian Semi

Two-storey rear extension — open-plan kitchen below, master bedroom with en-suite above. Full planning permission secured through Haringey.

48 sqm total 16 weeks Planning

View Full Extension Portfolio

4.9 on Google • 120+ reviews

Build Reviews

What Our Build Clients Say

“

The side-return extension completely transformed our ground floor. What was a dark, narrow kitchen is now a bright, open-plan room with a huge skylight running the full length. The architect suggested the glazed corner detail that everyone comments on — that's the difference between a design-and-build firm and a standard builder's extension.

Claire B.Side-return, Kentish Town NW5

“

We were worried about getting planning for a wraparound in a conservation area. Hampstead Renovations designed an extension with zinc cladding and a recessed glass link that the conservation officer praised as exemplary. The build was immaculate and the fixed price held exactly — not a single extra charge in 14 weeks of construction.

Alex S.Wraparound, Highgate N6

“

Having the kitchen designer, architect and structural engineer all working together from the start meant our extension was designed around our kitchen — not the other way round. The island position, the sink location, the pendant lighting — everything was resolved before the builders dug the foundations. No compromises, no changes on site.

James W.Rear extension, Hampstead NW3

Extension FAQs

House Extension Questions

Everything London homeowners ask about house extensions.

How much does a house extension cost in London?

Side-return extensions start from around £35,000, rear extensions from £45,000, wraparound extensions from £70,000 and double-storey extensions from £80,000. These are fully inclusive prices covering architectural design, structural engineering, planning, building regulations, the complete build and decoration. The cost per square metre ranges from £2,500 for a straightforward double-storey to £3,500+ for a premium single-storey with structural glass and high-specification finishes. We provide a fixed-price quotation after the design is agreed.

Do I need planning permission for an extension?

Many single-storey rear extensions fall within permitted development rights and don't require planning permission — up to 3m deep on terraced/semi-detached homes, or up to 6m under the larger home extension scheme (with prior approval notification). However, properties in conservation areas, Article 4 direction areas, flats, maisonettes and listed buildings have reduced or no PD rights. Double-storey extensions and side extensions on corner plots almost always require full planning permission. We assess the planning route at the free site visit.

How long does a house extension take?

The pre-construction phase (design, planning, engineering and party wall) typically takes 6–12 weeks depending on whether planning permission is required. The build phase takes 10–16 weeks: a side-return takes 10–12 weeks, a rear extension 12–14 weeks, a wraparound 12–16 weeks and a double-storey 14–16 weeks. In total, expect 5–7 months from first consultation to completion for a typical single-storey extension.

Can I live in the house during the extension?

Yes — virtually all our extension clients remain in the property throughout. The work is external for the first 4–6 weeks (foundations, walls, roof) and the opening between old and new is only created once the extension shell is weathertight. We set up a temporary kitchen arrangement and install dust barriers. The most disruptive period is the 2–3 days when the structural beam is installed and the internal opening is formed — after that, disruption decreases progressively.

Will an extension add value to my property?

Consistently. A well-designed extension in London adds approximately 15–25% to property value — typically exceeding the cost of construction. The value uplift is highest when the extension creates a genuinely usable open-plan kitchen-diner (the most sought-after feature for London buyers), incorporates good natural light and connects to the garden. A three-bedroom terrace with a narrow galley kitchen that becomes a three-bedroom home with a 30sqm kitchen-diner moves into a fundamentally different price bracket.

What is a side-return extension?

A side-return extension infills the narrow alley (typically 1–2m wide) that runs alongside the kitchen on Victorian and Edwardian terraced houses. Despite adding a relatively small floor area (8–15 sqm), the effect on the kitchen is transformative — it doubles the width of the room, allows a full-length skylight along the junction with the existing house and creates a dramatically brighter, more spacious cooking and dining area. It's London's most popular extension type because it delivers an outsized impact for a relatively modest cost.

Do I need a party wall agreement?

If your extension foundations are within 3m of a neighbouring wall (which applies to virtually all terraced and semi-detached extensions), you must serve a Party Wall Act notice on your neighbours at least two months before work starts. If the extension is built up to or astride the boundary line, a further notice type applies. We handle the entire party wall process in-house: drafting notices, commissioning schedules of condition and managing any party wall awards. This is included in our service, not charged as an additional fee.

What types of roofing can you do on an extension?

We offer flat roofs (the most common for single-storey London extensions, finished in EPDM, GRP or zinc), pitched roofs (slate, tile or zinc standing seam), structural glass roofs (for maximum overhead light), green/sedum roofs (increasingly popular for planning approvals and biodiversity) and combination designs that use a mix of glazed and solid sections. The roof design significantly affects both the interior quality of the extension and its external appearance from neighbours — we advise on the best approach for your specific property and planning context.

Local Expertise

Why Choose Us for House Extensions in Hampstead

We're not a national chain — we're a local design and build practice with deep roots in Hampstead and the surrounding neighbourhoods.

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Design Studio 2 minutes Away

Our design studio at 250 Finchley Road NW3 is just 2 minutes from Hampstead. Visit to see materials, meet the team, and discuss your project in person.

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Camden Planning Experts

Our RIBA architects have extensive experience with Camden Council's planning department, conservation officers, and building control team. We know what gets approved.

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We Know Hampstead Properties

From the Georgian townhouses, Victorian villas, Edwardian mansions and listed buildings on Church Row, Flask Walk, Frognal, Downshire Hill and Keats Grove — we understand the specific construction challenges and planning context of every property type in NW3.