Constructum Code is a London main contractor. We build to drawings produced by architects, interior designers and structural engineers.
Design stays with the practice that produced it. We price what is drawn, and where buildability or cost needs something to change, we raise it with you rather than resolve it on site.
Interested in this service?
For private clients
We build for private clients across London, most often to an architect’s drawings. Where you come to us before appointing anyone, we can introduce practices we have built for, and step back while the design is developed. Interior design, planning consultancy and specialist structural work are handled the same way — we point you to people we have worked with, and coordinate them within the build once the scheme is settled.
For architects and designers
How we are appointed
Single-stage tender. We price a fully designed scheme against drawings, specification and preliminaries, and return a tender with our assumptions and qualifications set out plainly rather than buried.
Two-stage. We come in earlier on preliminaries, overheads and track record, then develop buildability, sequencing and cost alongside the design before the contract sum is fixed. On refurbishment and on period buildings, this tends to produce the more reliable number, because the survey and any opening-up happen before the price is fixed rather than after.
Negotiated. Common on private residential work and repeat instructions, where the client wants certainty over competition.
During the build
We work under JCT, usually Minor Works or Intermediate, with the contract administrator running the process — interim valuations and progress meetings monthly or more often, instructions and variations priced and agreed as they arise.
Design queries come to you in writing rather than being resolved on site. Samples, substitutions and specialist subcontractor drawings are submitted for approval before anything is ordered. Where an element is specialist-designed — steelwork connections, glazing, waterproofing — it comes through the subcontractor’s design and goes to you for comment.
Prequalification
- Contracts: JCT Minor Works and Intermediate, with the form set by the complexity of the works rather than the value
- CDM 2015: we act as Principal Contractor, producing the construction phase plan, holding the risk assessments and method statements, and maintaining the information the Principal Designer needs for the health and safety file
- Insurance: £10m employers’ liability, £5m public liability, £1m professional indemnity, with certificates provided as standard at tender stage
- Accreditations: TrustMark registered, certified VELUX installation partner, registered with Certass and FairTrades
- Scale: our largest contract currently on site is £900,000, with a quantity surveyor and contract administrator appointed
- Sectors: residential extensions, loft conversions, basements and refurbishment; commercial offices, retail units and mixed-use premises
What we build
House extensions, loft conversions and commercial builds are our core work, mostly on Victorian and Edwardian housing stock across London. Around them we deliver basement conversions, refurbishment, roofing and windows, building services and the building control process.
Common questions
Do you take on design responsibility?
No — we build to your drawings and specification. Where an element is specialist-designed by its subcontractor, such as steelwork connections or a waterproofing system, that design is submitted to you for comment before it is fabricated or installed.
What do you need to tender?
Drawings, specification, any schedule of works, and the preliminaries. If a structural design or a waterproofing specification is still developing, tell us what is provisional and we will price it as such rather than assume.
Will you work with our contract administrator?
Yes, and we would expect to. Valuations, instructions and variations run through the contract administrator under the JCT form, and the certification at practical completion and the end of the rectification period runs the same way.
