London and Hertfordshire, UK

Loft Conversions


Dormer Loft Conversions

Hip to Gable Loft Conversions

L Shaped Loft Conversions

Mansard Loft Conversions


Lccl Construction customers say

4.9 Excellent

4.9 out of 5 based on 128 Reviews

"Excellent architecture services received, Lccl Construction has done a fantastic job with creating the architecture plans"

Review by Jade Morrison

Welcome to Lccl Construction, Loft conversion company, House extension builders, Architectural design services

Your trusted local architecture and construction company in London and Hertfordshire 

Covering London and Hertfordshire, United Kingdom

Covering London, United Kingdom and Surrounding Areas

Specialist Design and Build Construction Company 

Covering an 85 mile radius from our offices location in Finchley, London.

Architectural design and construction of house extensions. Rear single storey house extensions, side house extensions, wrap around house extensions, side return house extensions, two storey house extensions. We design and build house extensions in London and Hertfordshire.

Architectural design and construction of loft conversions. Dormer loft conversion, hip to gable loft conversions, L-shaped loft conversion, mansard loft conversion or velux loft conversion. We design and build loft conversions in London and Hertfordshire.

Architectural design services for loft conversions, house extensions and new build houses. Complete consultation package London and Hertfordshire, United Kingdom.

We can project manage your project on your behalf, with our construction management services we build loft conversions, home extensions, renovations and new builds.

Find out more about our construction process and stages, how do we go about running our construction project and what are the core elements associated in the construction process.

We can serve party wall notices, serve full party wall awards, liaison with 3rd party surveyors. Our party wall agreement services are conducted by surveyor who is MCIOB and FPWS accredited.

Our structural engineers produce structural design and structural calculations for your loft conversion, home extension, renovation or new build. 

New build scheme solution, we design and build your new house, our solutions of architecture and construction for new build homes, find out more.

Get instant quote for your loft conversion, home extension, upward home extension, renovation or new build including architecture and design build

Types of projects we do including architecture and construction, get your instant design and build quote 


Home extensions

  • Rear home extension

  • Side home extension

  • Side and rear extension

  • Wraparound 

  • Side return 

  • Two storey side

  • Two storey rear

  • Two storey wrap

  • First floor extension

  • Upward extensions


New build 


  • Detached homes

  • Terraced homes

  • Flats

Book consultation call for new build projects.

book consultation call >


Loft conversions


  • Dormer loft conversion

  • Hip to gable loft conversion

  • L shaped loft conversion

  • Mansard loft conversion

  • Velux loft conversion



  • Flat or apartment renovation

  • House renovation

  • Commercial to residential conversion including design and build 


Basement conversion 


  • Full house basement

  • Part house basement 

  • Outrigger basement


Upward extensions 


  • Detached up to two storey upwards

  • Bungalow single storey upwards

  • Terraced single storey upwards

  • Semi detached single storey upwards 


Book consultation call for upward extension projects.

book consultation call >

Get a free instant quote or book a free consultation call


Loft Conversion Design and Build

Lccl Construction unique construction process and design and build process for loft conversion and home extension 

Find out more about Lccl Construction unique construction process or design and build process and what happens on the design or construction stage. 

Step by step explanation of loft conversion, home extension and new build design and construction process. 

We have included our original project images taken on our construction projects.

Lccl construction design and build in London and Hertfordshire, United Kingdom is a specialist loft conversion company, house extension builders, architectural designers and planning company. With our end to end services we successfully start and finish every one of our projects. With our design and build construction company services we can complete all the stages of your build from consultation, architecture, survey to construction including plumbing and electrical installations under one roof. Our combined services includes planning, architectural design and construction. 

By providing services from start to finish we will deal with architecture, planning applications, planning negotiations, building control drawings, building control application, party wall survey and agreements, structural and construction drawings, production of the construction schedule, interior design, construction phase, dealing with building control during construction, electrical and plumbing installations, completion of the construction, certificate and Local Authority Building Control sign off. 

Loft Conversion Company London Limited trading as "Lccl Construction" Registration: 11713461

We cover all areas in London, Hertfordshire, United Kingdom. Our offices are located in 3rd Floor, Hathway House, Popes Drive, Finchley, London N3 1QF. The radius is 85 miles from our office location. Our phone number is: 020 8037 7332

What is a design and build company?

The design and build concept means that multiple specialist skills and trades are combined into one, from start to finish we will deal with all the architecture, consultation, planning and thereafter the entirety of the  construction, saving both time and capital.

We will help you plan, design and build your house extension or loft conversion every step of the way. 


Find out more about successfully completed Lccl Construction design and build projects portfolio click here


measured survey



party wall agreements

Architectural design, survey and construction services

lead consultant



structural engineer drawings