House
extensions
in Highbury, N5
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 Highbury house extensions across Highbury Fields, Highbury Place, Aberdeen Park - side-return, rear, wraparound and double-storey additions for Georgian terraces, Victorian villas and larger family homes where planning strategy, conservation detailing, Party Wall sequencing and structural engineering need handling properly.
House Extensions in Highbury: What You Need to Know
Every house extension project in Highbury is designed to respect the Highbury Fields Conservation Area and the character of Georgian terraces, Victorian villas, Edwardian mansion flats. Our in-house RIBA Chartered Architects handle Islington 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.
Highbury's conservation area status means extensions must be sensitively designed. Islington expects extensions to use matching or complementary materials and to respect the scale and character of the original building. We navigate these requirements daily.
Desirable residential area in Islington centred around Highbury Fields. Conservation area with handsome Victorian terraces, good schools and a village-like atmosphere around Highbury Barn. Side-return extensions are particularly popular in Highbury's terraced streets, transforming narrow kitchen spaces into full-width open-plan living areas connected to the garden.
Local character & heritage: extending in Highbury
Highbury is an elegant Islington district built around Highbury Fields — Georgian and Victorian terraces and squares, including Highbury Grove, prized as a family-house area. It sits in the London Borough of Islington, with conservation areas protecting its period streets.
The handsome terraced houses suit side-return and rear extensions to create open-plan family kitchens, plus loft and lower-ground conversions; houses split into flats need internal reconfiguration under the lease. Islington expects extensions to match the brick, proportions and rhythm of the terrace.
As across Islington, the borough's strict basement policy shapes lower-ground schemes (a Basement Impact Assessment is required), and tight terraced plots make party-wall and right-to-light matters routine. We plan the conservation, basement and neighbour issues up front.
Highbury heritage & architecture: Highbury Grove · Conservation areas explained · Renovating an N5 terrace · Period facades in N5 · Mansion flats · Listed buildings in N5 · Best family-home streets · Front gardens in N5
Highbury is unusual for how finely its roof rules are drawn. Gathered around Highbury Fields, it falls under the Highbury Fields Conservation Area (CA5), which takes in some of the finest Georgian terraces in the borough and the distinguished Victorian villas north of the Fields, with an Article 4 Direction in force. The register also lists Highbury New Park (CA15) and Aberdeen Park (CA27), so the first task on any extension is to fix which area governs the address.
Within Highbury Fields the council applies policy road by road: no roof additions or dormers across most of Highbury Park, Highbury Terrace and Leigh Road, existing mansards on parts of Highbury Place and Highbury Terrace kept as they are, and a traditional roof extension only where a property is scheduled. In Highbury New Park, laid out in the 1850s for grand detached and semi-detached houses, front and side roof slopes may take no new or altered dormers.
The stock spans Georgian and early-Victorian terraces, larger villas around Aberdeen Park and Edwardian mansion flats. On Islington figures a Highbury rear extension opens at roughly £71,250 to £112,500 before VAT, a side return near £90,000 to £120,000.
House Extensions in Highbury: Applied to the Local Stock
Highbury sits in the London Borough of Islington, gathered around the green expanse of Highbury Fields. The Highbury Fields Conservation Area (CA5) takes in some of the finest Georgian terraces in the borough fronting Highbury Fields and the distinguished Victorian villas north of the Fields from Highbury Hill to Aubert Park, together with the old village centre of Highbury Barn; an Article 4 Direction applies to the conservation area. Islington's register also designates Highbury New Park (CA15) and Aberdeen Park (CA27) as conservation areas; Highbury New Park was laid out in the 1850s as a fashionable development of grand detached and semi-detached houses, and no new or altered dormer windows are allowed on front or side roof slopes of properties in that area.
Within the Highbury Fields Conservation Area the council applies street-by-street roof policies: no roof extensions or dormers are permitted on most of Highbury Park, Highbury Terrace and Leigh Road, existing mansards on parts of Highbury Place and Highbury Terrace must remain unaltered, and traditional roof extensions may be permitted only on scheduled properties.
Sources: Islington Council, Highbury Fields (CA05) Conservation Area Design Guidelines (January 2002) (2026); Islington Council, Highbury New Park (CA15) Conservation Area Design Guidelines (January 2002) (2026)
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
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House Extensions in Highbury: Questions
Can I add a dormer or roof extension to a Highbury house?
It hinges on your exact street. Inside the Highbury Fields Conservation Area, Islington sets roof policy road by road: most of Highbury Park, Highbury Terrace and Leigh Road permit no roof extensions or dormers, existing mansards on parts of Highbury Place and Highbury Terrace must stay unaltered, and a traditional roof extension may be allowed only where a property is scheduled.
Which conservation areas cover Highbury?
Highbury gathers around Highbury Fields, and the Highbury Fields Conservation Area (CA5) embraces some of the borough's finest Georgian terraces facing the Fields plus the distinguished Victorian villas from Highbury Hill to Aubert Park, all under an Article 4 Direction. Islington's register also lists Highbury New Park (CA15) and Aberdeen Park (CA27).
Are there roof rules unique to Highbury New Park?
Using Islington headline ranges, a Highbury rear extension opens at roughly £71,250 to £112,500 before VAT. A side return tends to be dearer, near £90,000 to £120,000, with a wraparound inside an indicative £100,000 to £200,000 band. We translate those into a firm figure once the roof and layout approach is set against local policy.
What should I budget for a Highbury extension?
Using Islington headline ranges, a Highbury rear extension is put at £71,250–£112,500 before VAT, a side return a little higher at £90,000–£120,000, and a wraparound within an indicative £100,000–£200,000 band. We translate those into a firm figure once the roof and layout approach is set against local policy.
What kind of houses does Highbury offer for extending?
Highbury's stock is a confident blend of Georgian and early-Victorian terraces, larger Victorian villas around Aberdeen Park, and Edwardian mansion flats, much of it inside conservation areas that Islington guards closely. The larger Aberdeen Park villas in particular suit substantial whole-house refurbishment, lofts and rear additions.
How much does a house extension cost in Highbury, N5?
House extensions in Highbury typically cost £2,400–£3,800/sqm. A single-storey rear extension runs approximately £45,000–£85,000, while a double-storey extension costs £80,000–£160,000. Our fixed-price contracts include foundations, structural steelwork, full build and interior fit-out.
House Extensions in Highbury: Planning & Local Context
London Borough of Islington · N5
Planning for house extensions in Highbury
Rear and side-return extensions are popular in Highbury, but permitted-development rights are frequently restricted within the Highbury Fields Conservation Area, so most extensions need a full planning application to London Borough of Islington with design that respects the prevailing building line and materials.
London Borough of Islington & Highbury Fields Conservation Area context
Highbury N5 sits within the Highbury Fields Conservation Area, and Islington has one of London's strictest basement policies and extensive conservation-area coverage that removes most permitted-development rights. Our in-house RIBA Chartered Architects prepare and submit every application to London Borough of Islington and handle pre-application discussions where early planning advice is useful.
Building Regulations
House Extensions in Highbury 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 Highbury services — Kitchen Renovation Loft Conversions — or the Highbury renovation hub for the full picture of how we work locally.
Our in-house planning team prepares and submits every London Borough of Islington application and manages building control end to end. View our planning track record →
More Services in Highbury
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