About Constructum Code: London Main Contractor for Extensions, Lofts and Commercial Builds
Key takeaway: Constructum Code Ltd is a London main contractor specialising in house extensions, loft conversions and commercial builds. From our registered office in Loughton, Essex, we manage construction projects across South East London, Greater London and surrounding areas — from the initial site survey and structural review to planning coordination, construction, fit-out, building control inspections and handover.
Our delivery model brings structural masonry, steelwork, roof works, architectural glazing, building services and internal fit-out into one coordinated programme. Clients work with one project team rather than managing separate trades, suppliers and construction stages independently.
Constructum Code at a glance
Constructum Code delivers turnkey residential and commercial construction projects. We coordinate the project programme, procurement, structural works, specialist trades, quality checks and client communication from early planning through to completion.
Legal name
Constructum Code Ltd
Company Registration Number
15031868
VAT Number
454907667
Registered office
Ground Floor Office, Unit 10a Loughton Business Centre, Langston Road, Loughton, Essex, IG10 3FL, United Kingdom
Primary service area
South East London, Greater London and surrounding boroughs
Company established
2023
Leadership experience
Over 20 years of hands-on construction, site management and project delivery experience
Project delivery capacity
A coordinated team of approximately 20 to 30 skilled construction professionals and specialist trades
Our three core construction services
Constructum Code concentrates on structural construction projects that require careful sequencing, building-control coordination and high-quality internal finishes. Our three principal services are house extensions, loft conversions and commercial builds.
House extensions in South East and Greater London
We design and build side-return, rear, wrap-around and double-storey house extensions. Extensions create additional living space for open-plan kitchen-diners, family rooms, bedrooms, home offices and improved connections to gardens without the cost and disruption of moving home.
Our project scope can include site assessment, architectural coordination, structural calculations, foundation groundworks, steel fabrication, brickwork, roof alterations, architectural glazing, plumbing, electrical installations and final decoration.
We deliver dormer, Mansard, hip-to-gable and roof-light loft conversions that transform roof space into bedrooms, home offices, guest rooms or principal suites. Each conversion is planned around roof geometry, head height, existing structure, party wall conditions and fire-safety requirements.
Our scope includes structural steel insertion, roof framing, thermal insulation, VELUX roof-window installation, bespoke staircases, plumbing, electrical works, plastering, joinery and final finishing.
We deliver commercial construction work for offices, retail units, hospitality spaces, landlords and business owners. Projects can include structural alterations, CAT A and CAT B fit-outs, commercial partitioning, acoustic improvements, building-services coordination and layout reconfiguration for practical business operations.
We work with commercial clients, architects, interior designers and project surveyors to coordinate construction around the approved specification, operational requirements and agreed programme.
Supporting services are integrated where needed to deliver a complete house extension, loft conversion or commercial-build programme. They are coordinated as part of the main construction project rather than delivered as disconnected tasks.
Basement conversion and excavation works where outward or upward extension is constrained by site boundaries;
Full or partial property refurbishment connected to an extension, loft conversion or commercial fit-out;
Structural engineering calculations, steelwork fabrication, underpinning, masonry, roofing and weatherproofing;
Planning applications, permitted-development assessment and Party Wall Act coordination where applicable;
Electrical, plumbing, central heating, underfloor heating, insulation, plastering, joinery and decoration;
Coordination with architects, structural engineers, interior designers, surveyors and specialist suppliers.
Our main-contractor model is designed for clients planning substantial residential or commercial construction work who want coordinated delivery, structural oversight, transparent cost control and one project contact.
Our services are suited to
Homeowners planning major house extensions, dormer or Mansard loft conversions, and substantial property transformations;
Property owners considering basement conversion where planning, boundaries or site constraints limit outward development;
Property developers and investors seeking one main contractor for refurbishments, conversions and structural work;
Architects and interior designers looking for a construction delivery partner for complex approved drawings and specifications.
Projects outside our primary focus
Minor handyman repairs, cosmetic redecoration and isolated maintenance work with no construction scope;
Projects where the client wishes to source, schedule and manage all individual trades independently;
Projects outside South East London, Greater London and the immediate surrounding service area.
What a main contractor does on a London construction project
A main contractor coordinates the construction programme, site operations, procurement, specialist trades and client communication. This approach gives the project one delivery structure for structural works, roofing, services, fit-out and handover.
Where appointed in writing by the client as Principal Contractor on a project involving more than one contractor, Constructum Code plans, manages, monitors and coordinates the construction phase under the Construction (Design and Management) Regulations 2015.
Comparing project delivery models for London structural projects
The procurement route affects project communication, construction sequencing, budget management, design coordination and the division of responsibilities. The right route depends on the client’s priorities, the design status and the complexity of the project.
Project delivery model
Accountability and management
Cost and change control
Design, compliance and site coordination
Single Main Contractor (Constructum Code)
One project contact for the agreed construction scope, procurement, programme, site activity and specialist-trade coordination.
Where the scope and project information are sufficiently defined, clients receive an itemised fixed-price quotation. Variations are reviewed, priced and agreed in writing before additional work proceeds.
Construction stages are coordinated with architects, engineers, party wall surveyors and building control bodies. Principal Contractor duties apply where Constructum Code is formally appointed under CDM 2015.
Direct Coordination of Individual Trades
The client or an appointed manager coordinates separate contractors, suppliers, construction stages and technical interfaces.
Changes can require separate quotations, procurement decisions and programme updates with several individual contractors.
The client must arrange appropriate design, CDM dutyholder and building-control appointments where required.
Architect-Led Procurement
An architect or design team leads the design process, while a separately appointed contractor manages construction delivery under the selected building contract.
Tendering, cost planning, contract administration, valuations and variation procedures depend on the procurement route and the level of completed design information.
Responsibilities are allocated between the client, design consultants, contractor and building control body. This model suits design-led projects where design development and site delivery are actively coordinated.
Managing structural risks on London construction projects
London’s Victorian, Edwardian and Georgian housing stock can involve shallow footings, ageing party walls, historic settlement, hidden alterations and restricted urban access. Constructum Code uses a structured pre-construction and site-management approach to identify constraints before and during construction.
Laser-guided load path auditing: before opening up floors, removing walls or installing structural steel, we conduct laser-guided surveys of existing walls, floor levels and visible load-bearing lines. This review helps compare actual site conditions with the available drawings and the proposed structural-engineering calculations.
Integrated trade sequencing: structural masonry, steelwork, carpentry, roofing, weatherproofing, mechanical first-fix and internal fit-out are sequenced through one construction programme to reduce clashes between trades and minimise avoidable exposure of the building envelope.
Building control hold-points: we plan inspection points before foundations, structural junctions, damp-proofing, insulation and other work stages that will later be concealed. Relevant checks, records and inspection requests are coordinated before the project progresses.
Structured change control: if an unforeseen condition or client variation arises, the issue is documented, assessed, priced and agreed before additional work proceeds.
Laser-guided site review supports project planning and construction coordination. Structural design, calculations and specialist surveys are undertaken by appropriately qualified professionals where required.
How we deliver your project
Every project follows a defined delivery process designed to give clients visibility over decisions, programme, construction activity, budget and scope changes.
Consultation and site assessment: we discuss project goals, evaluate property conditions, assess access, review initial budget expectations and identify visible structural constraints.
Planning and technical coordination: we review drawings, coordinate structural-engineering calculations, manage permitted-development assessment or planning submissions, and coordinate party wall procedures where applicable.
Project scope, programme and pricing: once the required project information is sufficiently defined, we prepare an itemised quotation, baseline construction programme, material specifications and delivery milestones. Changes are reviewed and agreed in writing before additional work proceeds.
Structural construction and fit-out: our site teams coordinate foundations, steelwork, brickwork, roofing, weatherproofing, mechanical services, plumbing, electrical installations and internal finishes.
Handover and completion: we complete the agreed works, provide relevant handover information and coordinate applicable building-control inspection and completion stages.
Construction work in London may require planning permission, permitted-development assessment, structural-engineering calculations, party wall notices, building control approval and other technical documentation. The relevant route depends on the property, the scope of work, location and statutory requirements.
Where included in the agreed scope, Constructum Code liaises with clients, architects, structural engineers, party wall surveyors, local planning authorities, approved inspectors and registered building control bodies. For official guidance, consult UK Government information on Building Regulations approval and the Planning Portal.
Constructum Code Ltd is listed as a TrustMark Registered Business. The company also states that it holds trade registrations with Certass and FairTrades and is a certified VELUX installation partner for roof-window systems used in loft conversion projects.
Leadership, site management and building services
Constructum Code projects are delivered through a coordinated team of project managers, site managers, building-services professionals and specialist trades. Team roles are assigned according to the structural, services and fit-out requirements of each project.
Ben Vitkauskas — Founder and Managing Director, leading project operations and quality assurance with more than 20 years of construction and site leadership experience;
Roland Bujokas — Site Manager Lead, specialising in groundworks, structural masonry, steelwork installation and first-fix coordination;
Robert King — Site Manager Lead, overseeing internal fit-outs, joinery, carpentry and second-fix delivery;
Remis Gudavicius — Building Services Lead for heating, plumbing and domestic gas systems;
Robert Salminas — Senior Project Manager with international construction-management experience;
Remis Gudavicius is Gas Safe registered and holds CCN1 Gas Safety, LCWR 23 Water Regulations and LCL Level 3 Air Source Heat Pump certifications.
Client feedback and completed project examples
“Fantastic experience with the Constructum team. We had a side return and extension completed in Clapham, and the job was done brilliantly. Communication with Ben throughout the project was regular and clear.”
“I’m very happy with the loft conversion and kitchen extension Constructum Code completed at my house in Bromley. Ben, the manager, kept good communication and came across as a very fair and honest man.”
Frequently asked questions about construction projects in London
What are Constructum Code’s main services?
Our three core services are house extensions, loft conversions and commercial builds. Basement conversions, refurbishment, planning coordination and specialist trades are supporting services provided where needed for a core project.
What is the difference between a main contractor and individual trade contractors?
A main contractor coordinates the agreed construction scope, programme, procurement, site operations, specialist trades and client communication. Individual trades typically deliver their own work package, while overall project coordination depends on the client’s chosen delivery structure and appointments.
Where does Constructum Code work?
Constructum Code Ltd has its registered office in Loughton, Essex, and delivers residential and commercial projects across South East London, Greater London and surrounding boroughs.
How long does a house extension or loft conversion take?
The programme depends on design status, structural complexity, access, planning, party wall requirements, procurement lead times, weather conditions and the scope of internal works. After the site assessment and review of available information, we provide a baseline programme showing the proposed construction sequence and key milestones.
Do you manage party wall and building control requirements?
Where included in the agreed scope, Constructum Code coordinates with qualified party wall surveyors, structural engineers and building control bodies. Where party wall procedures apply, notices and any necessary agreements or awards should be addressed before the relevant notifiable works begin.
Can homeowners remain in their property during construction?
This depends on the scope, access, utility requirements and health-and-safety arrangements for the project. During the site consultation, we discuss work-zone separation, temporary services and measures to manage disruption. For larger structural remodelling projects, temporary relocation may be advisable for safety and comfort.
Discuss your London construction project with Constructum Code
Contact our project team to discuss a house extension, loft conversion or commercial build, arrange an initial site consultation, or review structural feasibility and budget estimates.
Constructum Code Ltd
Company Registration Number: 15031868
VAT Number: 454907667
Registered Office: Ground Floor Office, Unit 10a Loughton Business Centre, Langston Road, Loughton, Essex, IG10 3FL, United Kingdom
Constructum Code was established in 2023, bringing together experienced construction professionals to deliver residential and commercial projects across London and the surrounding areas. Our team of skilled tradespeople, site and project managers works closely with architects and interior designers to manage each project from first survey through to completion.
The company’s Founder and Managing Director, Ben Vitkauskas, brings more than 20 years of construction experience, having worked in site and project management roles across the UK and overseas. He remains hands-on across every major project, working alongside the site and project managers who run each build day to day.
Our Name & Meaning
The name Constructum Code is derived from Latin. Constructum means “built,” reflecting the company’s focus on creating high-quality, enduring structures. Code signifies the principles and standards that guide every project: precision, consistency, and attention to detail.
Our Leadership Team
Ben Vitkauskas
Founder, Managing Director
Ben Vitkauskas
Ben brings 20+ years in construction and team leadership to every project, overseeing them personally to ensure precision and quality at every stage. He manages daily operations and joins his team on site visits to stay hands-on with every build. Off-site, Ben enjoys outdoor activities and quiet time in nature.
Remis Gudavicius
Building Services Lead
Remis Gudavicius
Gas Safe registered, Remis leads building services, specialising in domestic gas systems, central heating, and water heaters. He holds CCN1 Gas Safety, LCWR 23 Water Regulations, and LCL Level 3 Air Source Heat Pump certifications. A devoted basketball player, he enjoys both playing and following the sport in his free time.
Gyte Gavenaite
Creative Associate
Gyte Gavenaite
Gytė contributes to the company's visual representation by capturing imagery that supports how Constructum Code showcases its residential and commercial projects. Outside of her work, she is interested in personal growth and the relationship between emotion and visual expression, while also developing her own photography projects.
Robert King
Site Manager Lead
Robert King
Robert has over 20 years of site management experience and oversees the company’s site managers and projects, specialising in second-fix work. He is also a keen sauna enthusiast.
Robert Salminas
Project Manager
Robert Salminas
Having managed projects in the UK, Sweden, and Norway for 25+ years, Robert is a certified project manager with extensive international experience. A competitive boxer in his youth, he applies the same focus and discipline to every project he oversees.
Roland Bujokas
Site Manager Lead
Roland Bujokas
Roland brings 20+ years of site management experience, specialising in structural work and first-fix projects, while overseeing site managers and coordinating teams to ensure every project runs smoothly. In his downtime, he enjoys kayaking.
Gvidas Venckaitis
Strategy & Growth Adviser
Gvidas Venckaitis
Gvidas provides strategic guidance to help the company enhance its market presence. Most recently, he worked at a leading London public affairs firm, advising top-tier clients across multiple sectors, and brings over a decade of experience in policy, politics, and consulting. In his free time, he enjoys history books and following his beloved Liverpool FC.
Where we work
We deliver residential and commercial construction projects across London and nearby areas.
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Constructum Code is a London construction company specialising in high-quality house extensions, loft conversions and commercial builds for private and business clients.
