One Company. Every Service. Across London.
London's residential property market demands more from builders than anywhere else in the country. Conservation areas, listed buildings, complex planning authorities, terraced house structural challenges, basement regulations, party wall requirements — and homeowners who expect premium results because their properties are worth premium prices.
LCCL Construction is an LABC Building Excellence Award-winning design and build company delivering house extensions, loft conversions, renovations, and architectural services across London. We provide the complete service in-house: architecture, structural engineering, planning applications, construction, and project management. One team, one contract, one quote covering everything.
Based in Finchley N3, we serve North London, Central London, West London, South West London, and selected areas of East and South East London. Our strongest presence is across North and North West London, but our conservation area expertise, period property experience, and award-winning construction quality travel well — which is why homeowners in Hampstead, Islington, Kensington, Fulham, Clapham, and Richmond all choose to work with us.
Find Your Area
We maintain dedicated pages for every area we serve, with local pricing, planning guidance, and project information specific to that neighbourhood's housing stock and planning authority. Browse our area pages or call 020 8037 7332 for a free consultation.
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 Across London
Every London extension is shaped by its context. A rear extension on a Fulham terrace involves different structural considerations from a wraparound on a Barnet semi. A basement extension in Kensington navigates RBKC's strict SPD policies while a loft conversion in Enfield proceeds under straightforward permitted development. Our experience spans the full range.
What makes LCCL different from most London builders is the integrated approach. Our architects design with construction costs in mind from day one. Our engineers anticipate the structural challenges — party walls, shallow Victorian foundations, load-bearing wall removals — at the design stage rather than discovering them on site. The result: fewer surprises, accurate quotes, and projects that run to programme.
Extension Costs Across London
Rear Extensions — £40,000 in outer boroughs to £140,000+ in prime central London.
Side Return Infills — £35,000–£80,000. Transforms the ground floor of Victorian terraces.
Double-Storey Extensions — £85,000–£280,000+. For properties with sufficient plot space.
Basement Extensions — £150,000–£600,000+. Subject to borough-specific policies.
What Is Included
All prices include: architecture, structural engineering, planning applications, all construction, project management, building control via LABC, and 10-year LABC warranty. All-inclusive quote. Call 020 8037 7332.
- LOFT CONVERSIONS
Loft Conversions Across London
London's housing stock offers loft conversion potential across virtually every property type. The hipped roofs on interwar semis respond to hip-to-gable conversions. Victorian terraces suit rear dormers and mansard extensions. Edwardian properties have generous roof volumes. Even some postwar homes have viable loft spaces once assessed properly.
The planning context varies by borough and conservation area status. Most conversions outside conservation areas qualify under permitted development. Within conservation areas — which cover substantial portions of Camden, Islington, Kensington & Chelsea, Hampstead, Highgate, and many other areas — planning permission is required. Our architects design proposals that satisfy conservation officers across every London borough we work in.
Loft Conversion Costs Across London
Rear Dormers — £42,000–£90,000. The most popular option across all London areas.
Hip-to-Gable — £46,000–£95,000. Ideal for interwar semis across outer London.
Mansard Conversions — £60,000–£120,000+. Maximum space for terraced properties.
L-Shaped Dormers — £55,000–£100,000. For end-of-terrace properties combining rear and side elements.
What Is Included
All prices include: architecture, structural engineering, scaffolding, all construction, staircase, insulation, electrics, en-suite plumbing, building control via LABC, project management, and 10-year LABC warranty. Call 020 8037 7332.
- RENOVATIONS
Renovations Across London
London's period properties — Georgian, Victorian, Edwardian — were designed for a different era. Separate reception rooms, below-stairs kitchens, outside bathrooms, and dated services don't match how modern families live. A well-planned renovation reconfigures these beautiful properties for contemporary life while preserving the character that makes them valuable.
LCCL delivers renovations from single-room refits to complete whole-house refurbishments. Structural reconfiguration with steel beams, high-specification kitchens and bathrooms, rewiring, replumbing, heating upgrades, period feature restoration, and insulation improvements compatible with solid-wall construction. For listed buildings, our architects manage Listed Building Consent applications alongside the construction programme.
Costs vary by specification and scope: kitchen renovations £24,000–£90,000, bathroom renovations £11,000–£40,000, structural reconfiguration £5,000–£22,000, whole-house refurbishment from £85,000 upward.
- ARCHITECTURE
In-House Architecture Across London
London has 33 planning authorities, each with its own policies, conservation area designations, and officer expectations. Our architects submit regularly to Barnet, Haringey, Camden, Islington, Hackney, Enfield, Westminster, Kensington & Chelsea, Hammersmith & Fulham, Wandsworth, Lambeth, Richmond, Brent, and Ealing. That breadth of experience means we understand not just good design, but what each authority will approve — and how to present applications that get through efficiently.
The integrated design and build model is our competitive advantage. Architecture, engineering, and construction sit under one roof. Designs are always buildable. Quotes are always accurate. There's no gap between what the drawings promise and what the finished project delivers.
Every London project includes: measured survey, concept designs, 3D visualisations, construction drawings, planning applications or LDCs, structural engineering, and building regulations via LABC. All included in your quote — no separate architect fees.
- LOCA PLANNING EXPERTISE
Planning Across London
Planning Authorities
London's planning landscape is uniquely complex. Over 1,000 conservation areas across the capital, thousands of listed buildings, and 33 planning authorities with distinct policies. Our strongest planning relationships are with North and Central London boroughs: Barnet, Camden, Haringey, Islington, Hackney, Enfield, and Westminster.
Wider London Coverage
We also submit regularly to Kensington & Chelsea, Hammersmith & Fulham, Wandsworth, Lambeth, Richmond, Brent, and Ealing. Each borough has different conservation area policies, basement development restrictions, and design expectations for period property alterations.
Key Considerations
Key considerations that vary by borough: conservation area extent and Article 4 Directions, basement development policies (particularly Camden, Westminster, RBKC), permitted development rights and their local restrictions, design expectations for period property alterations, and heritage statement requirements.
Typical Planning Timescales
Householder applications across London target 8-week decisions. We manage the complete process from measured survey to planning approval.
Permitted Development
Standard PD rights apply outside conservation areas. Within London's 1,000+ conservation areas, rights are restricted and planning permission is usually required for external alterations. We assess each property individually and recommend the most efficient route to approval.
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
Which parts of London do you cover?
North London (our home territory), Central London, West London, South West London, and selected areas of East and South East London. See our area pages for specific locations with local pricing and planning detail.
Why choose LCCL over a local builder?
We're not choosing between local knowledge and professional capability — we offer both. LABC Building Excellence Award Winners 2024, 200+ reviews at 4.7/5, complete in-house design and build with architecture, engineering, and construction under one roof. Most London builders can't match that combination.
How much does an extension cost in London?
Costs vary significantly by area: rear extensions £40,000–£140,000+, side returns £35,000–£80,000, double-storey £85,000–£280,000+. See our area pages for location-specific pricing. All LCCL quotes include architecture, engineering, planning, construction, and 10-year LABC warranty.
What's included in your price?
Everything: architecture, structural engineering, planning applications, all construction, project management, building control via LABC, and 10-year LABC warranty. Transparent pricing. Final costs confirmed once designs are agreed.
How do I get started?
Call 020 8037 7332 or book a free consultation. We visit your property, discuss your plans, and give honest advice. Free, no obligation.
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