Loft conversions, house extensions, renovations, basements and new builds across London and Hertfordshire.
Services
Loft conversions, house extensions, renovations, basements and new builds across London and Hertfordshire.
Services
Loft conversions, house extensions, renovations, basements and new builds across London and Hertfordshire.
Services
Loft conversions, house extensions, renovations, basements and new builds across London and Hertfordshire.
Services
Call 020 8037 7332 or get an instant estimate online.
Kitchen extensions · London & Hertfordshire
Kitchen extension London: cost, design and build time — from £42,000 inc. VAT (£35,000 + VAT) plus fit-out
By Anderson & the LCCL Construction Team
Finchley N3 · Design & build, LABC award winners 2024 and 2026
Most London extensions are kitchen extensions: the point of the extra space is an open-plan kitchen, dining and living room that opens onto the garden. This page gives you the 2026 numbers for the build and for the fit-out separately — because the kitchen itself is the part clients most often under-budget — plus the layouts that work, the planning routes and how one team designs, builds and fits it.
Quick answer
£42,000 – £153,600 inc. VAT (£35,000 – £128,000 + VAT) for the extension build (rear, side return or wraparound) plus £9,000 – £87,360 inc. VAT (£7,500 – £72,800 + VAT) for the kitchen itself, supplied and fitted, by size and specification. Design and build inclusive. Postcode dependent.
Depends on the shape: rear and side return extensions are usually permitted development; a wraparound usually needs a planning application.
12–16 weeks on site including the fit-out; 8–16 weeks of design and approvals before that.
A free 30-minute phone call with our team, no obligation.
Guide price
£42,000 – £153,600 inc. VAT (£35,000 – £128,000 + VAT) + fit-out
Typical build
12–16 weeks on site
Guarantee
12-month workmanship guarantee; 10-year LABC structural warranty
Awards
LABC 2024 & 2026 winners
LABC Building Excellence Award 2024
Best Residential Extension in London — Bohun Grove, East Barnet EN4: rear extension, hip-to-gable loft conversion and whole-house renovation
LABC Building Excellence Awards 2026
London Regional Winner, Best Conversion or Alteration — Weech Road, Hampstead NW6: penthouse loft conversion and full renovation
One contract
Architecture, structural engineering, planning, construction and project management — all under one contract
Guaranteed & insured
12-month workmanship guarantee; 10-year LABC structural warranty
What a kitchen extension from LCCL includes
Design and build inclusive, and we fit the kitchen — one contract from the drawings to the last cupboard door.
Measured survey of the house and garden
Architectural design and drawings, with revisions until you're happy
Planning application or Lawful Development Certificate, prepared and submitted for you
Building regulations drawings and structural calculations by our chartered engineer
Party wall notices served on your behalf (£300 each, at cost)
Foundations, drainage and any build-over agreement with Thames Water
Structure, roof, rooflights, doors and windows to a weather-tight shell
Plaster finish, first-fix electrics and plumbing, underfloor heating where specified
Fitting of the kitchen you choose — units, worktops, appliances, splashbacks — plus flooring and second-fix
LABC inspections and completion certificate
A dedicated project manager and a weekly progress update
12-month workmanship guarantee; 10-year LABC structural warranty
How much does a kitchen extension cost in London in 2026?
Two numbers: the extension build, then the kitchen fit-out. Every project is priced from your postcode and house type.
Extension shape
Typical use
Build range
Rear extension 3–6 m
Kitchen extended into a kitchen-diner with garden doors
£42,000 – £90,000 inc. VAT (£35,000 – £75,000 + VAT)
Side return infill
Galley kitchen widened to full width, glazed roof
£42,000 – £93,600 inc. VAT (£35,000 – £78,000 + VAT)
Wraparound side + rear
Full-width kitchen, dining and living in one L-shaped room
£72,000 – £153,600 inc. VAT (£60,000 – £128,000 + VAT)
Kitchen fit-out
Guide range
Notes
Mid-range kitchen
Rigid units, quartz or composite worktop, fitted and connected (appliances extra)
£16,200 – £56,160 inc. VAT (£13,500 – £46,800 + VAT) by kitchen size
Most of our projects
High-specification kitchen
Bespoke or premium units, stone worktops, island with seating (appliances extra)
£25,200 – £87,360 inc. VAT (£21,000 – £72,800 + VAT) by kitchen size
Bohun Grove EN4 level
Kitchen renovation without an extension
New kitchen in the existing footprint, supplied and fitted (openings priced separately)
£9,000 – £87,360 inc. VAT (£7,500 – £72,800 + VAT)
See home renovation
What the build price includes: survey, architectural drawings, lawful development certificate or planning, building-regulations drawings, structural calculations, construction to plaster finish with first-fix electrics and plumbing, underfloor heating where specified, LABC sign-off and guarantees. The fit-out price is the kitchen itself — units, worktops, appliances, splashbacks, sink and taps — which we fit as part of the contract. The figure on your itemised estimate is the figure you pay — nothing is added afterwards. Postcode dependent — the instant estimator adjusts the range for your area in thirty seconds, and a detailed itemised estimate follows one survey.
What moves the price: the extension shape (a wraparound costs most because of the corner steel and the glazing); rooflights and the doors to the garden; how much of the back and outrigger walls come out — on a Victorian terrace budget £4,000–£12,000 of steel; moving the drainage, gas and water to a new kitchen position; and the kitchen specification, which can vary by £60,000 on the same room.
Kitchen extension layouts by house type
Victorian or Edwardian terrace
The galley kitchen in the outrigger becomes a full-width kitchen-diner by filling the side return, extending the outrigger, or both. The island sits under the rooflights, the dining table at the garden end, and the old kitchen space becomes a utility or pantry.
1930s semi
A full-width 3–4 m rear extension across the back. The kitchen usually moves from the front or side of the house into the new space, with the dining area against the garden doors and the old kitchen becoming a utility, WC or study.
Flat or maisonette
Kitchen extensions to ground-floor flats need a planning application (no permitted development for flats) and the freeholder's consent. Layouts are the same; the approvals take longer.
Planning
Do you need planning permission for a kitchen extension?
It depends on the shape of the extension, not on it being a kitchen.
Extension shape
Usual route
Time
What we do
Rear extension to 3 m (4 m detached)
Permitted development
No application
Lawful Development Certificate, ~8 weeks, included
Rear extension to 6 m (8 m detached)
Prior approval (larger home extension)
42 days
Neighbour notification submission prepared by us
Side return within PD limits
Permitted development
No application
Lawful Development Certificate included
Wraparound, flats, conservation areas
Full planning
8 weeks
Drawings, design statement and application by our team
Building regulations & party walls
The other two approvals
Every extension needs building-regulations approval whether or not it needs planning: foundations, structure, insulation, glazing area, drainage and fire. We do this through LABC with full-plans drawings and our own structural calculations, so the inspector is checking a design he has already approved, not improvising on site.
If the extension is on or near the boundary of a semi or terrace, the Party Wall Act applies. Notices go out at least two months before we start; most neighbours consent, and where a surveyor is appointed we manage it.
Whatever the planning route, a kitchen extension always needs building-regulations approval — and a kitchen has its own rules on extract ventilation, gas, electrics and the escape route from the room. We design to them from the start so the LABC inspector is signing off a plan he has already approved.
Recent kitchen extension projects
Bohun Grove, East Barnet EN4 — rear extension, hip-to-gable loft and whole-house renovation
LABC 2024 Best Residential Extension in London
Semi-detached family home One programme loft + extension + renovation
A total renovation of a family semi: a rear extension opening into a full-width kitchen and dining space with floor-to-ceiling glazing and skylights, a hip-to-gable loft conversion with a rear dormer, two Lusso Stone bathrooms, enlarged bedrooms, new windows throughout, a regulated outbuilding and landscaping.
Because the loft and extension ran under one contract, the steelwork for the open-plan ground floor and the loft floor was designed together and lifted in on the same day — one crane hire, one scaffold, one building-control file.
See the Bohun Grove project · All projects
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ANDERSON · FOUNDER, LCCL CONSTRUCTION
Anderson's advice: put the rooflights over the island
Rooflights over kitchen islands transform natural light more than any other single design decision. We position them on the plan before the kitchen layout is fixed, not after — moving a rooflight on a drawing costs nothing; moving one in a finished roof costs a week.
The second thing we say on every call: decide where the dining table goes first. Everything else — doors, lighting, the run of the units — follows from that.
How a kitchen extension runs with LCCL
From the first call to the completion certificate. We agree the date the old kitchen comes out with you in advance and set up a temporary kitchen where the house allows.
WEEK 0
Free consultation call
A 30-minute phone call with our team about the house, what you want from the space and a realistic budget. Your instant estimate is the starting point.
WEEKS 1–4
Survey & design
Measured survey, architectural drawings and your detailed itemised estimate — design, planning, structure, construction and warranty priced line by line. The kitchen layout is drawn at this stage so the rooflights, drainage and electrics are positioned around it.
WEEKS 4–12
Approvals
Lawful Development Certificate or planning application, building-regulations drawings, structural calculations, party wall notices. Nothing starts on site until it is signed off.
BUILD
On site
12–16 weeks on site for a kitchen extension including the fit-out. Weekly updates from your project manager, one point of contact throughout.
HANDOVER
Sign-off
Snagging, LABC final inspection and completion certificate, guarantees in writing. 10-year LABC structural warranty.
“We used Lccl construction first time for our kitchen extension 2019 with a view to build a loft conversion afterwards. We just have had our loft conversion completed including bedroom, bathroom, storage loft it has Juliet balcony with velux windows to the…”
Tracie · Trustpilot
“We engaged with LCCL Construction to get our loft conversion and house extension project going. The whole process was explained to us in a straight forward way including how the design stages work, timescales, what to expect during the build and the costs…”
Daniel Freedman · Trustpilot
“I highly recommend LCCL Construction. They completed our loft conversion to a very high standard, and the quality of workmanship throughout was excellent. The team was professional, reliable, and completed everything within a very reasonable timeframe.…”
Alina A · Google Reviews
Kitchen extension questions we get asked most
Two numbers in 2026: £42,000 – £153,600 inc. VAT (£35,000 – £128,000 + VAT) for the extension build depending on whether it is a rear, side return or wraparound, and £9,000 – £87,360 inc. VAT (£7,500 – £72,800 + VAT) for the kitchen itself, supplied and fitted, by size and specification depending on specification. Both are design and build inclusive and we fit the kitchen under the same contract.
Because it is the part clients most often under-budget. Two identical extensions can differ by £60,000 on the kitchen alone. Pricing the build and the fit-out separately means you can see exactly where the money goes and decide the specification with the numbers in front of you.
It depends on the shape, not on it being a kitchen. A rear extension to 3 m or a side return within the limits is permitted development; a rear extension to 6 m goes through prior approval; a wraparound, a flat or a conservation-area house needs a full application. We check your address before the first drawing.
Twelve to sixteen weeks on site including the kitchen fit-out, plus 8–16 weeks before that for design and approvals. The extension is built as a shell before the old kitchen comes out, so you keep a working kitchen for most of the programme.
Under the rooflights. Rooflights over the island transform the light in the room more than any other design decision, so we position them on the plan before the kitchen layout is fixed. Decide where the dining table goes first; the island, the doors and the run of units follow from that.
Yes. Most clients buy the kitchen from a supplier of their choice and we fit it, coordinate the delivery with the programme and make sure the first-fix services are where the units need them. We can also recommend suppliers we have worked with.
Most clients do. The shell is built first, the back wall comes out at an agreed date, and we set up a temporary kitchen where the house allows. The weeks without a full kitchen are usually four to six.
An open-plan kitchen-diner is the improvement most London buyers pay for. Our house-extension value guide sets out what the data shows by area. We are not valuers, so treat any figure as indicative and talk to a local agent before you commit.
Where we build kitchen extensions
From Finchley N3 we cover North London, North-West London, Central London, South-West and West London, and Hertfordshire — and we also work across the rest of London, Buckinghamshire, Surrey, Kent and Essex. Recent kitchen extensions: Mill Hill NW7, Maida Vale W9 and Finchley N3.