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.
Wraparound extensions · London & Hertfordshire
Wraparound extension London: cost, planning and build time — from £72,000 inc. VAT (£60,000 + VAT)
By Anderson & the LCCL Construction Team
Finchley N3 · Design & build, LABC award winners 2024 and 2026
A wraparound fills the side return and extends across the back at the same time, giving an L-shaped, full-width kitchen, dining and living space in one build. It is the biggest ground-floor change you can make to a terrace or semi without going up a storey. This page covers the 2026 numbers, why a wraparound usually needs a planning application, the layouts that work, and how the job runs with one team.
Quick answer
£72,000 – £153,600 inc. VAT (£60,000 – £128,000 + VAT) for a single-storey wraparound extension, design and build inclusive (kitchen on top). Postcode dependent.
Usually a planning application: side and rear together normally exceed permitted development limits. Some wraparounds split into PD side + prior-approval rear.
14–18 weeks on site; 8–16 weeks of design and approvals before that.
A free 30-minute phone call with our team, no obligation.
Guide price
£72,000 – £153,600 inc. VAT (£60,000 – £128,000 + VAT)
Typical build
14–18 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 wraparound extension from LCCL includes
Design and build inclusive — the price covers the whole job, not just the bricks.
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, flooring and second-fix items you supply
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 wraparound extension cost in London in 2026?
Guide ranges, design and build inclusive. Every project is priced from your postcode and house type.
Size (footprint)
Typical use
Guide range
Side return + 3 m rear (≈25–30 m²)
Full-width kitchen-diner, garden doors across the back
£72,000 – £102,000 inc. VAT (£60,000 – £85,000 + VAT)
Side return + 4–5 m rear (≈30–40 m²)
Kitchen, dining and a seating area, utility off the side
£96,000 – £132,000 inc. VAT (£80,000 – £110,000 + VAT)
Side return + 6 m rear (≈40–50 m²)
Open-plan kitchen, dining, living and utility, large glazing spans
£126,000 – £153,600 inc. VAT (£105,000 – £128,000 + VAT)
Related extension
Guide range
On site
Side return only
Width without the rear step-out
£42,000 – £93,600 inc. VAT (£35,000 – £78,000 + VAT)
10–14 wks
Rear extension only
Depth without the side return
£42,000 – £90,000 inc. VAT (£35,000 – £75,000 + VAT)
10–14 wks
Double-storey wraparound
Wraparound below, bedrooms above — always a planning application
£90,000 – £198,000 inc. VAT (£75,000 – £165,000 + VAT)+
16–24 wks
What the price includes: survey, architectural drawings, planning application, building-regulations drawings, structural calculations, construction to plaster finish with first-fix electrics and plumbing, LABC sign-off and guarantees. On top: the kitchen itself, supplied and fitted (£9,000 – £87,360 inc. VAT (£7,500 – £72,800 + VAT) by size and specification; appliances extra), flooring and second-fix items you choose. 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 rear depth more than the side width; the length of the steel across the corner where the two wings meet (the single largest structural item); glazing — corner-less sliding doors and a run of rooflights are the biggest variable; a flat roof with lanterns versus a pitched or part-glazed roof; drainage rerouted around the new footprint; and the finish inside.
Wraparound extensions by house type
Victorian terrace
The side return is filled and the outrigger extended 3–4 m, so the kitchen runs the full width and the dining space sits at the back. The outrigger wall comes out onto a long steel. A planning application is the norm because the side and rear elements together exceed permitted development; a well-designed scheme with a flat roof and rooflights is routinely approved.
1930s or Edwardian semi
The side passage is filled (often keeping a 1 m access) and a 3–4 m rear extension runs across the back. On a semi the attached neighbour gets a party wall notice and the detached side needs the 2 m boundary height rule respected. Barnet-area semis are our most common wraparound.
Detached house
Rare — with 4 m of rear permitted development and no side return to fill, most detached houses get a full-width rear extension instead. Where a side extension is wanted for a utility or garage conversion, we design it as a separate PD element.
Planning
Do you need planning permission for a wraparound extension?
Usually yes. The side and rear elements together normally exceed what permitted development allows, so most wraparounds go through a full application.
Route
When it applies
Time
What we do
1. Full planning
Most wraparounds — side + rear together exceed PD limits; conservation and Article 4 areas
8 weeks
Drawings, design statement, precedent search and application by our team
2. Split route
Side return within PD limits + rear to 3 m (or 6 m by prior approval) built as separate elements
42 days + LDC
Two submissions where the design and the council allow it
3. Pre-application advice
Larger schemes, sensitive streets, boroughs that engage
4–6 weeks
We advise whether it is worth the fee for your borough
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.
A wraparound is the extension type most likely to be refused on daylight and outlook grounds to the attached neighbour — the 45-degree rule is applied to the rear wing. Keeping the rear depth to 3–4 m, the roof flat and the eaves at 3 m near the boundary gets most schemes through first time. Where the borough is helpful on pre-application advice we use it; where it is not, we rely on precedent.
Planning permission for house extensions · Wraparound extension cost guide
Recent wraparound 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 wraparound extension runs with LCCL
From the first call to the completion certificate. Because a wraparound usually needs a full planning application, allow 12–16 weeks for design and approvals before work starts.
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.
WEEKS 4–12
Approvals
Planning application (eight-week decision), building-regulations drawings, structural calculations, party wall notices to both neighbours. Nothing starts on site until it is signed off.
BUILD
On site
14–18 weeks on site for a single-storey wraparound extension. 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.
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Wraparound extension questions we get asked most
£72,000 – £153,600 inc. VAT (£60,000 – £128,000 + VAT) in 2026, design and build inclusive — survey, drawings, planning application, structural calculations, construction to plaster finish and building-control sign-off. Side return plus a 3 m rear sits at the bottom of the range; side return plus a 6 m rear with large glazing at the top. The kitchen is on top.
Usually yes. Permitted development allows a side extension or a rear extension, but the two together normally exceed the limits, so most wraparounds go through a full planning application with an eight-week decision. A minority can be split into a PD side return and a prior-approval rear; we tell you which applies to your address before the first drawing.
Fourteen to eighteen weeks on site, plus 12–16 weeks for design, planning and building regulations before that. It is the longest single-storey programme because there are two wings, a corner steel and more glazing than a straight rear extension.
Nothing — they are the same thing. The extension wraps around the outrigger of a terrace or the side passage of a semi, so the footprint is L-shaped on the plan.
If you want a full-width kitchen and a dining or living space at the back, yes — it is the only single-storey option that gives both. If you only need one of those, a side return or a rear extension does it for £42,000 – £93,600 inc. VAT (£35,000 – £78,000 + VAT) and usually without a planning application.
It can, which is why it needs planning. The rear wing is tested against the attached neighbour's nearest window using the 45-degree rule; keeping the depth to 3–4 m and the roof flat is what gets schemes approved. We also serve party wall notices to both neighbours.
Yes — many clients keep a 1 m passage or fit a door in the new side wall. It is a design decision we settle on the survey visit.
Yes, and it costs less than doing them a year apart because the scaffold, the structural design and the party wall process are shared. See our loft + extension page for how the two are programmed together.
Where we build wraparound 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 wraparound extensions: Chelsea SW10, Hendon NW4 and East Barnet EN4.