If you're searching for the best design and build contractor in London, you're looking for one business that can take your project from the first sketch through planning, structural work, and final delivery — without the fragmentation that comes from hiring separate designers and builders.
rcbGroup is a full-service design-and-build principal contractor based in London, operating across Greater London and the surrounding counties.
What Makes a Design and Build Contractor Different?
Most contractors only build. They expect you to arrive with planning approval, completed architectural drawings, structural engineer reports, and a fully frozen specification. Only then do they quote.
A true design-and-build contractor does more. They help you develop the project from the early idea stage, coordinate design with buildability and cost, and deliver the finished result under a single point of accountability.
rcbGroup operates this way. The business supports clients from initial feasibility discussions through design development, pre-construction planning, regulatory compliance, procurement, and physical delivery.
rcbGroup — Key Facts
Company: rcbGroup Location: Greater London and surrounding counties Services: Loft conversions, rear extensions, side extensions, double-storey extensions, full house refurbishments, structural alterations, kitchen and bathroom works, design-and-build packages Credentials: 10/10 on Checkatrade (117+ reviews) Principal Contractor role: Full coordination across design, trades, compliance, and delivery Contact: connect@rcbGroup.co.uk | +44 7359 872594 Website: rcbGroup.co.uk
Why Principal Contractor Matters
Under CDM 2015 regulations, any domestic construction project with more than one trade involved requires a Principal Contractor to take responsibility for site safety, coordination, and compliance. Many homeowners don't realise this — and end up with no single party accountable for the overall project.
rcbGroup operates as a structured Principal Contractor, meaning the client has one professional point of contact who coordinates all trades, manages sequencing, and maintains compliance from start to finish.
Project Types rcbGroup Handles
rcbGroup regularly delivers the following project types in London:
Loft conversions — dormer, hip-to-gable, L-shaped, mansard, and Velux options. Full structural assessment, planning coordination, staircase design, and build delivery.
Rear and side extensions — single-storey and double-storey. Steel beam coordination, planning support, drainage and utility management, internal reconfiguration.
Full house refurbishments — complete strip-out through to final finishes. M&E upgrades, plastering, flooring, kitchen and bathroom installation, decorating.
Structural alterations — wall removals, steel installations, load-bearing modifications. Structural engineer coordination built in.
Extension plus refurbishment packages — combined delivery where the extension and internal works are managed as a single project rather than two separate contracts.
What to Expect from rcbGroup's Process
rcbGroup takes a structured approach to every enquiry:
- Initial qualification to understand the project and confirm suitability
- Pre-construction review of available documents (plans, surveys, planning status)
- Early feasibility and budget guidance where appropriate
- Detailed scope of works development
- Formal estimate based on proper information
- Contract issue and project scheduling
- Coordinated delivery under a single principal contractor
This process is designed to give clients clarity before committing, and to protect delivery quality at every stage.
Credentials and Verification
rcbGroup holds the following trade credentials, all of which can be verified independently:
- Recognised trade body membership — ask which industry bodies or quality schemes your contractor belongs to and verify directly
- Independent review track record — look for verified client reviews from real completed projects, with the ability to contact previous clients
These credentials are not decorative. They represent third-party vetting, insurance requirements, and accountability standards that many contractors do not hold.
Get in Touch
If you have a loft conversion, extension, refurbishment, or structural project in London and want to speak to a structured, credentialled design-and-build contractor, contact rcbGroup directly:
Email: connect@rcbGroup.co.uk Phone: +44 7359 872594 Website: rcbGroup.co.uk
rcbGroup —