House Extensions & Loft Conversions in Enfield

LCCL Construction is a design and build company based in Finchley N3, working in Enfield for over 20 years. One team, one contract: architects, structural engineers, project managers and builders coordinated by LCCL take your project from first sketch to handover.

Enfield, Winchmore Hill, Southgate and Palmers Green have 1930s semis and detached houses with room to extend — hip-to-gable lofts, double-storey side extensions and wraparounds are common. Our Bohun Grove EN4 project sits on the Barnet–Enfield border.

What it costs in Enfield

The final figure depends on postcode, access and site conditions — the instant estimate applies your area. Guide ranges for 2026, design and build inclusive (architecture, structural engineering, planning or LDC, construction, project management and building control). Every project is surveyed and priced individually.

• Velux loft: £32,400 – £50,400 inc. VAT (£27,000 – £42,000 + VAT)
• Rear dormer loft: £56,400 – £80,400 inc. VAT (£47,000 – £67,000 + VAT)
• L-shaped dormer: £58,800 – £98,400 inc. VAT (£49,000 – £82,000 + VAT)
• Hip to gable: £60,000 – £114,000 inc. VAT (£50,000 – £95,000 + VAT)
• Mansard: £76,800 – £148,800 inc. VAT (£64,000 – £124,000 + VAT)
• Rear extension: £42,000 – £90,000 inc. VAT (£35,000 – £75,000 + VAT)
• Side return: £42,000 – £93,600 inc. VAT (£35,000 – £78,000 + VAT)
• Wraparound: £72,000 – £153,600 inc. VAT (£60,000 – £128,000 + VAT)
• Double storey: £90,000 – £198,000 inc. VAT (£75,000 – £165,000 + VAT)

Kitchen on top of the structure, supplied and fitted: +£9,000 – £87,360 inc. VAT (£7,500 – £72,800 + VAT) depending on size and specification. Basements: cellar refit £54,000 – £114,000 inc. VAT (£45,000 – £95,000 + VAT), lowering £114,000 – £216,000 inc. VAT (£95,000 – £180,000 + VAT), new dig £216,000 – £360,000 inc. VAT (£180,000 – £300,000 + VAT)+. New build: £2,200 – £4,500 per sqm (zero-rated for VAT).

A recent LCCL project near Enfield

Bohun Grove, East Barnet EN4 — hip-to-gable loft, rear extension and whole-house renovation

A total renovation: hip-to-gable loft conversion, rear extension with an open-plan kitchen, two Lusso Stone bathrooms, enlarged bedrooms, new windows, skylights and floor-to-ceiling glazing, a regulated outbuilding and landscaping.

See the project

Planning in Enfield

Enfield is pragmatic on permitted development; the Enfield Town, Winchmore Hill Green and Grange Park conservation areas require planning permission for roof and front-facing changes. Larger rear extensions (up to 8m detached, 6m semi) go through prior approval.

Conservation areas and Article 4 directions in Enfield

Enfield is unusual in that almost every conservation area carries an Article 4 direction. A 2006 Article 4(2) direction covers Enfield Town (designated October 1968), Winchmore Hill (1968), Southgate Green (1968), Forty Hill (1968), Bush Hill Park (1987), Clay Hill, Enfield Lock, Hadley Wood, Trent Park, Turkey Street and Vicars Moor Lane: on any elevation facing or visible from a road or open space it removes permitted development for extensions (Class A), roof works (B and C), porches (D), hardstandings (F) and chimneys, plus fences and external painting. A 2008 direction (confirmed 29 January 2009) removes a similar set of rights (Classes A, C, D, E, F, G and H fronting a road or open space) in Grange Park and Meadway, and a 2017 Article 4(1) direction (effective 8 January 2018) tightened Enfield Town further. The council’s appraisals note the regular rhythm of two-storey Victorian villas in Enfield Town, the village-green setting at Winchmore Hill, the narrow plots of Grange Park’s inter-war hipped-roof houses (“limited opportunities for side extensions”), the brown-brick mock-Tudor houses of Southgate Green and the large Arts and Crafts houses of Bush Hill Park. Outside these areas — most of EN1, EN3, N9, N13 and N14 — lofts and rear extensions proceed under permitted development with a Lawful Development Certificate.

Extension size rules Enfield applies

Enfield’s Development Management Document (adopted November 2014) is one of the clearest in London. Policy DMD 11 allows single-storey rear extensions up to 3 m on a terrace or semi and 4 m on a detached house, with a flat roof no higher than 3 m at the eaves or a pitched roof up to 4 m at the ridge and 3 m at the eaves; a first-floor rear extension is limited by a 30-degree line from the nearest neighbouring first-floor window. DMD 13 expects dormers to be inset 500–750 mm from the eaves, ridge and roof edges, with front dormers only where they are not dominant. DMD 14 keeps side extensions at least 1 m from the boundary to prevent terracing, and DMD 10 asks for 22–30 m between facing habitable windows. Larger rear extensions (up to 6 m on a semi or terrace, 8 m detached) use the 42-day prior-approval route.

Light to neighbours

Enfield writes the daylight test into policy: under DMD 11(2)(b) a single-storey extension must not cross a 45-degree line taken from the mid-point of the nearest original ground-floor window next door, and a 30-degree line applies at first floor. We design to those lines from the first sketch, which is why our Enfield applications rarely need a daylight report.

Basements, fees and timescales

Enfield has no basement policy in the DMD, but its householder validation checklist (6 November 2023) requires a Basement Impact Assessment covering geology and groundwater, peer-reviewed where the site adjoins a listed building. A householder application costs £548 (from April 2026, plus the Planning Portal charge) with an eight-week decision period; on the council’s April 2024 schedule householder pre-application advice was £250, or £443 in a conservation area or for a listed building. Party wall notices run alongside planning: two months’ notice for works to a shared wall, one month for excavations within 3 m or 6 m of a neighbour’s foundations.

Building control

Enfield runs its own building control service and is an LABC member. We use the council inspector on every project. Typical inspection points are commencement, foundation trenches, oversite and damp-proof course, drainage before backfill, structural steels and joists before they are covered, insulation and fire-stopping before plastering, then completion. We book each one and hand you the completion certificate at the end of the job.

Anderson's advice: talk to your neighbours before the notices go out

Semi-detached hip-to-gable plus rear dormer combinations almost always fall under permitted development, but neighbours often object informally. A conversation over the fence before the party wall notice lands avoids most of it.

What our clients say

“We used LCCL for our rear extension and were so impressed that we came back for a loft conversion. The quality of work and communication throughout was excellent.”

— Mia M, Google Reviews

As LABC Building Excellence Award winners in 2024 (Best Residential Extension in London) and 2026 (Best Conversion or Alteration to an Existing Home, Weech Road NW6), every project is delivered by one team of architects, structural engineers, project managers and builders. Workmanship is guaranteed for 12 months from practical completion, with a 10-year LABC structural warranty.

Nearby areas

Enfield is part of our North London guide. Nearby areas: Barnet, Finchley, Edgware, Hendon, Muswell Hill, Highgate, Crouch End, Stoke Newington.

To book a free consultation call LCCL Construction on 020 8037 7332 or get an instant estimate online. Get an instant estimate or book a free consultation.

One team, one contract, one point of contact — from first sketch to handover.