Loft conversions, extensions & refurbishments done properly.
One team, fixed price, full accountability — from first survey to Building Regulations sign-off. Checkatrade 9.96/10 · FMB registered · 25-year structural warranty.
Or call 07359 872594
What we build
We deliver the full design-and-build package — not just the labour. One team from planning to sign-off.
Loft Conversions
Dormer, hip-to-gable, L-shaped dormer and Velux conversions. Most without planning permission. 6–10 weeks on site.
House Extensions
Single and double-storey rear, side and wraparound extensions. Prior approval or permitted development. Fixed price before we start.
Full Refurbishments
Whole-house and flat refurbishments. Strip out to finish. We manage structural, M&E, plastering, joinery, and fit-out.
Structural Alterations
Load-bearing wall removal, steel beam installation, structural opening creation. Structural engineer coordinated. Building Control managed.
HMO Conversions
Licensed HMO fit-out and conversion. Fire compartmentation, escape routes, licensing compliance. We know what Building Control needs.
Garage Conversions
Integral or detached garage conversion to habitable room. Building Regulations managed. 4–6 weeks on site.
How we work
We operate as a principal contractor — one point of contact from survey to completion. Not a trades broker. Not a loose network.
Free survey
We visit, assess and give you a fixed-price indication.
Design & planning
We coordinate design, planning and structural engineer input.
Fixed price
Detailed scope and fixed price agreed in writing before start.
Managed build
We manage all trades and procurement. One call handles everything.
Sign-off + warranty
Building Regs completion certificate and 25-year warranty.
Why choose RCB Design & Build?
Most builders give you a quote. We give you a plan. We operate as a structured, design-led principal contractor — which means one team takes responsibility for every part of your project, from the structural engineer through to Building Control sign-off.
Our 9.96/10 Checkatrade rating from 114+ independently verified reviews reflects how we work: on time, on budget, with a single point of contact throughout.
Book your free surveyFixed-price guarantee
Your price is fixed before we start. We absorb cost movements — not you.
25-year structural warranty
All structural work is covered under our long-term warranty.
Principal contractor model
One team manages every trade, every supplier, every inspection.
Design-and-build capability
We support design development, planning and pre-construction cost planning.
9.96/10 Checkatrade
Independently verified from 114+ homeowners across London.
Where we work
We are based in East London and work across 35+ London boroughs and towns.
Ready to get started?
Book a free survey. No obligation. Fixed price before we touch a single brick.