House Extensions & Loft Conversions in Camden

LCCL Construction is a design and build company based in Finchley N3, working in Camden 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.

Camden Town, Kentish Town and Primrose Hill are Victorian terraces and villas, many split into flats. Rear and side-return extensions, roof extensions to top-floor flats and whole-house renovations are the typical projects; access and neighbour management are half the job.

What it costs in Camden

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 Camden

Weech Road, Hampstead NW6 — penthouse duplex loft conversion

A top-floor flat turned into a penthouse duplex: the kitchen and living space moved up into the new loft, two new bathrooms, an extra bedroom and views across to the Shard, the London Eye and Parliament. LABC Building Excellence Awards 2026 London Regional Winner — Best Conversion or Alteration to an Existing Home.

See the project

Planning in Camden

Camden has extensive conservation areas (Primrose Hill, Camden Town, Kentish Town) and Article 4 directions; most roof work needs planning permission. Basements need a Basement Impact Assessment under Camden's policy.

Conservation areas and Article 4 directions in Camden Town, Primrose Hill and Kentish Town

Primrose Hill (designated 1971) covers the mid-19th-century stock-brick terraces with stucco dressings around Regent’s Park Road and Chalcot Square and has an Article 4 direction dating from 3 March 1983. Camden Town (1986) takes in the 1820–50 grid of terraces between Camden High Street and the canal, and Kentish Town covers the flat-fronted parapet terraces off Kentish Town Road and Leighton Road; neither has an Article 4 direction, so front-facing replacement windows remain permitted development there, but roof, side and two-storey rear extensions on conservation-area terraces need planning permission and careful detailing. Outside the conservation areas — parts of Gospel Oak, Somers Town and the NW5 streets towards Tufnell Park — lofts and single-storey rear extensions usually proceed on a Lawful Development Certificate.

The rules Camden applies

Camden’s Home Improvements planning guidance (CPG, adopted 15 January 2021) is qualitative rather than numerical: rear extensions must be subordinate to the house and leave a reasonably sized garden (para 2.1.1), side extensions should be single storey (2.1.2) and roof extensions and dormers must stay subordinate to the roof slope (2.2). The same guidance requires the 45-degree and 25-degree daylight tests from the BRE guide, or a full BRE daylight assessment, so we run the 45-degree check on every Camden design before it goes in.

Basements are the borough’s strictest area. A borough-wide Article 4 direction (made 13 September 2016, in force 1 June 2017) means every basement excavation needs planning permission. Local Plan policy A5 and the Basements CPG limit a basement to one storey, no more than 50% of each garden, less than 1.5 times the footprint of the house and no further than 50% of the house’s depth beyond the rear wall, set back from the boundaries. Every application needs a Basement Impact Assessment prepared by a chartered engineer or geologist and independently audited at the applicant’s cost.

Fees and timescales

A householder application costs £548 (from April 2026, plus the Planning Portal service charge) with an eight-week decision period. Camden’s homeowner pre-application service is £481.50 (level 1) or £963 (level 2) including VAT, and the council adds a £46 administration fee to applications sent by email. 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

Camden runs its own building control service and aims to decide full-plans applications within six weeks. 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: start the party wall process early

Most clients underestimate the party wall timeline — it can add three months to a semi-detached or terraced project. We raise it at the first meeting so notices go out while the design is still being finalised, not after.

What our clients say

“We have used Lccl in the past for our rear house extension and have come back to instruct Lccl for our loft conversion too to our house in North London. As before we are very happy with the services from Lccl and we highly recommend their design and construction services for both home extension or loft conversion including both design and build services.”

— 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

Camden is part of our Central London guide. Nearby areas: Islington, Kensington & Chelsea, Notting Hill.

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.