A kitchen extension is one of the most transformative improvements you can make to your home. By extending the footprint of your property, you gain a spacious kitchen, kitchen-diner, or open-plan kitchen-living area that becomes the true heart of the house. RCB Design & Build handles every aspect of the project as principal contractor under CDM 2015 — from planning and structural engineering through groundworks, foundations, steelwork, brickwork, roofing, insulation, electrics, plumbing, plastering, and decoration. Second-fix materials (kitchen units, worktops, tiles, flooring, and appliances) are client-supplied so you keep full control over the interior specification and budget. We coordinate the structural build and the kitchen fit-out as one seamless project.
Extend the back of your property to create a larger kitchen with direct access to the garden through bi-fold or sliding doors.
Fill the narrow alleyway beside Victorian and Edwardian terraces to widen the kitchen, adding valuable floor area without reducing garden space.
Combine a rear and side return extension into an L-shaped build, creating a generous kitchen-diner with room for a large island and dining table.
Remove internal walls and extend outwards to create a single flowing space that combines kitchen, dining, and living areas.
A brick-built orangery extension with a lantern roof, creating a light-filled kitchen space with a premium architectural finish.
Kitchen extensions in London and the South East typically cost between £40,000 and £90,000, depending on size, structural complexity, and specification. A small rear extension starts around £40,000, while a large wraparound kitchen-diner with premium finishes can reach £90,000 or more. We provide a fixed written quotation after a site visit.
Many single-storey rear kitchen extensions fall under permitted development rights if they meet size and height criteria. Side return and wraparound extensions may require a full planning application depending on the site. We assess your permitted development allowance during the free site visit and advise on the best planning route.
A rear kitchen extension typically takes 10–12 weeks on site. Wraparound and larger open-plan builds take 12–16 weeks. We provide a detailed construction programme so you know exactly when your new kitchen will be ready.
We fit and install the kitchen, but the units, worktops, appliances, and tiles are client-supplied (second-fix materials). This means you choose your kitchen from any supplier — IKEA, Howdens, or bespoke joinery — at whatever budget suits you, with no builder markup. We coordinate delivery timing to match our build programme.
Yes. We regularly combine kitchen extensions with internal wall removal (RSJ installation), loft conversions, and full house refurbishments. Doing everything under one contract with one project manager is more efficient and cost-effective than running separate projects.
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