Award-Winning Design & Build in the Royal Borough
Kensington and Chelsea is the most planning-restricted borough in London. The vast majority of the Royal Borough is designated as conservation area, and RBKC's planning policies on extensions, loft conversions, and particularly basement development are among the strictest in the country. Building here demands a level of architectural expertise and planning knowledge that most construction companies simply don't have.
LCCL Construction is an LABC Award-winning design and build company with over 20 years' experience delivering residential projects to the highest standards. We provide the complete service in-house: architecture, structural engineering, planning applications, construction, and project management. One team, one quote, one company responsible for the result.
We serve Kensington and Chelsea from our base in Finchley N3. We work in the Royal Borough because our clients' properties — and RBKC's exacting planning standards — demand the quality of workmanship and design that we deliver.
Why Kensington & Chelsea Homeowners Choose LCCL
LABC Building Excellence Award Winners 2024 — Independent recognition of the highest construction standards in the UK.
200+ Reviews Averaging 4.7/5 — Consistent quality across hundreds of projects, verified by real homeowners.
RBKC Planning Expertise — Our architects understand the Royal Borough's specific policies on conservation areas, basement development, and residential alterations.
Complete Design & Build — Architecture, engineering, planning, construction, project management, and 10-year LABC warranty. Transparent pricing with no hidden extras. Final costs confirmed once designs and structural requirements are agreed.
Our Services
Design and build under one roof, Architecture, planning, construction, and finishing — managed by one team, from start to finish.
- HOUSE EXTENSIONS
House Extensions in Kensington & Chelsea — Working Within RBKC's Strict Planning Framework
Extensions in the Royal Borough require careful navigation of RBKC's conservation area policies. Almost all properties sit within a conservation area, and the council applies rigorous design standards to any proposed extension. Materials, proportions, detailing, and the impact on neighbouring properties are all scrutinised carefully. Despite this, well-designed extensions are regularly approved.
Extension Types for Kensington & Chelsea Properties
Rear Extensions — The most achievable extension type in RBKC. Single-storey rear additions in sympathetic materials are generally supported where they don't harm the character of the conservation area or the amenity of neighbours. For the Victorian terraces that dominate much of the borough, rear extensions can create substantial kitchen-dining spaces. Typical costs: £75,000 to £140,000.
Side Return Extensions — Infilling the narrow side return passage alongside a Victorian terrace kitchen is one of the most effective space-gaining strategies in RBKC. This modest alteration makes a significant difference to the ground floor. Often combined with a rear extension for maximum impact. Typical costs: £55,000 to £80,000.
Basement Extensions — RBKC introduced its Basement Development Supplementary Planning Document in 2016, placing strict controls on subterranean development. Basements are limited to single-storey, must not extend under gardens beyond 50 percent of the garden area, and require comprehensive structural assessments, construction management plans, and neighbour impact studies. Despite these restrictions, single-storey basement extensions remain a viable and popular way to add space in the Royal Borough. Typical costs: £250,000 to £500,000+.
Wraparound Extensions — Combining rear and side elements to maximise ground-floor space. Best suited to end-of-terrace or corner properties where the side extension doesn't impact a shared party wall. Typical costs: £100,000 to £180,000.
What Is Included in Every Extension Quote
All prices include: in-house architectural design, structural engineering, planning applications to RBKC, heritage and design statements, all construction, project management, building control via LABC, and a 10-year LABC warranty. All-inclusive — no hidden extras. Call 020 8037 7332.
- LOFT CONVERSIONS
Loft Conversions in Kensington & Chelsea — Roofscape Sensitivity
Loft conversions in RBKC are subject to the borough's strict conservation area policies. The council places particular importance on protecting roofscapes, and proposals must demonstrate that dormers, roof extensions, and other alterations don't harm the character of the conservation area when viewed from surrounding streets and buildings.
That said, loft conversions are regularly approved in Kensington and Chelsea. Rear dormers that are not visible from the street, mansard extensions on appropriate properties, and sensitive rooflight installations are all achievable with the right architectural approach.
Loft Conversion Types for RBKC Properties
Rear Dormer Conversions — The most commonly approved conversion type in the Royal Borough. A well-proportioned rear dormer preserves the front roofline and streetscape while creating a spacious room with full standing headroom. RBKC scrutinises dormer proportions, materials, and relationship to the existing roof carefully. Costs: £60,000 to £90,000.
Mansard Conversions — Where the local roofscape already includes mansard forms, RBKC may approve a mansard conversion that matches the established character. Requires full planning permission and detailed justification. Creates the maximum usable space. Costs: £80,000 to £120,000+.
Rooflight-Only Conversions — The least contentious option in planning terms. Conservation-style flush rooflights on the rear slope provide natural light without altering the roofline. Suitable for listed buildings or the most sensitive locations. Costs: £45,000 to £65,000.
L-Shaped Dormers — For end-of-terrace properties where both rear and side dormers are achievable without impacting the streetscape. Maximises loft floor area. Costs: £70,000 to £100,000.
What Is Included in Every Loft Conversion Quote
All prices include: in-house architectural design, structural engineering, planning applications to RBKC, scaffolding, all construction, staircase, insulation, electrics, en-suite plumbing, building control via LABC, project management, and a 10-year LABC warranty. No hidden extras. Call 020 8037 7332.
- RENOVATIONS
Renovations in Kensington & Chelsea — Premium Specification, Period Sensitivity
The Royal Borough's housing stock includes some of London's most valuable and architecturally significant residential properties. Georgian townhouses in Chelsea, stucco-fronted Victorian villas in South Kensington, red-brick mansion blocks, and elegant terraces across the borough all present opportunities for comprehensive renovation at the highest specification.
Renovation work in RBKC frequently involves structural reconfiguration, bespoke kitchen and bathroom installations, full rewiring and replumbing, restoration of period features, and upgrading insulation and heating systems to modern standards while respecting the building's character. For listed buildings, Listed Building Consent may be required for internal alterations.
Typical renovation costs in Kensington and Chelsea: kitchen renovation £40,000 to £90,000, bathroom renovation £18,000 to £40,000, structural reconfiguration £10,000 to £22,000, whole-house refurbishment from £150,000 upward. Detailed quotes provided. Final costs confirmed once designs and structural requirements are agreed.
- ARCHITECTURE
In-House Architecture — RBKC Conservation & Basement Specialists
RBKC's planning policies are among the most prescriptive in London. The borough's approach to conservation areas, basement development, and residential alterations requires architects who understand not just good design, but the specific policy framework that governs what RBKC will approve. The Basement Development SPD, the conservation area appraisals, and the borough's design standards all need to be navigated with care.
LCCL's in-house architects submit applications to RBKC and understand the borough's expectations. The integrated design and build model ensures designs are buildable and accurately costed from the outset — no redesigns when the builder's price doesn't match the architect's vision.
Every Kensington and Chelsea project includes: measured survey, concept designs, 3D visualisations, construction drawings, planning applications to RBKC, heritage and design statements, structural engineering, and building regulations via LABC. All included in your quote — no separate architect fees.
- LOCA PLANNING EXPERTISE
Planning & Local Knowledge — Kensington & Chelsea
Planning Authority
Properties in the Royal Borough fall under the Royal Borough of Kensington and Chelsea (RBKC). RBKC is one of London's most restrictive planning authorities, with comprehensive policies on conservation areas, basement development, and residential alterations.
Conservation Areas
The vast majority of RBKC is designated as conservation area. Over 30 conservation areas cover the borough, including major designations such as the Royal Hospital Conservation Area (Chelsea), The Boltons Conservation Area, Kensington Square Conservation Area, Ladbroke Conservation Area, and Thurloe and Smith's Charity Conservation Area (South Kensington). Permitted development rights are restricted throughout these areas.
Basement Development Policy
RBKC adopted its Basement Development Supplementary Planning Document in 2016, introducing some of London's strictest controls on subterranean development. Key requirements include: basements limited to single storey beneath the building footprint, no basements extending under more than 50 percent of the garden area, structural methodology statements by chartered engineers, construction traffic management plans, flood risk assessments, and assessments of impact on neighbouring properties and trees. Our team manages the complete basement application process.
Listed Buildings
The Royal Borough contains thousands of listed buildings. Any work to a listed building — internal or external — requires Listed Building Consent from RBKC. Applications must demonstrate that the proposed work preserves the building's special architectural and historic interest.
Typical Planning Timescales
Householder planning application: 8-week target decision. Listed Building Consent: 8 weeks. Basement applications: 8–13 weeks (often require specialist reports). Pre-application advice: available and strongly recommended for complex proposals. Building control: inspections throughout, final sign-off at completion.
Building Control
All LCCL projects are managed through LABC building control. Inspections at each key stage ensure compliance with Building Regulations. At completion, you receive a building control completion certificate and optional 10-year LABC warranty.
Frequently Asked Questions
Can I extend my property in Kensington and Chelsea?
Yes, but most extensions require planning permission from RBKC because the vast majority of the borough is conservation area. Well-designed rear extensions, side return infills, and basement extensions are regularly approved. Our architects handle all applications.
How much does an extension cost in Kensington & Chelsea?
Rear extensions: £75,000 to £140,000. Side return: £55,000 to £80,000. Basement: £250,000 to £500,000+. All LCCL prices include architecture, engineering, planning, construction, and 10-year LABC warranty.
What are the basement rules in RBKC?
RBKC limits basements to single storey, requires structural assessments, construction management plans, and limits garden excavation to 50 percent of the garden area. Despite these restrictions, basement extensions remain viable and popular. We manage the entire process.
Can I convert my loft in the conservation area?
Yes. Rear dormers and sensitive loft conversions are regularly approved. RBKC pays particular attention to roofscape impact. Our architects design proposals that satisfy conservation officers. Costs from £60,000.
Do you work on listed buildings?
Yes. We have experience with listed buildings and understand the requirements for Listed Building Consent from RBKC.
Areas We Cover
Based in Finchley N3, serving London and Hertfordshire.
North London and Hertfordshire
Barnet | Finchley | Hendon | Muswell Hill | Edgware | Enfield | Borehamwood | Potters Bar | Watford | St Albans
Across London
Hampstead | St Johns Wood | Islington | Kensington & Chelsea | Fulham | Clapham | Richmond | Putney & Wandsworth | Crouch End | Stoke Newington | Highgate | Ealing | Notting Hill | Camden | Queens Park