One of the first questions clients ask when they come to us is a simple one: “What will this cost?” It is a fair question, and the honest answer is that design and build project costs in London vary considerably depending on the scope, specification, and complexity of the work involved.

That said, there are realistic benchmarks you should know before you start budgeting, and understanding what drives costs up or down will help you plan with confidence.

What Is a Design and Build Project?

Before looking at costs, it is worth clarifying what a design and build project actually includes. Unlike hiring an architect and contractor separately, a design and build company manages the entire process under one contract, from initial concept and interior design through to construction, fit-out, and final handover.

This single-contract model typically reduces risk, shortens timelines, and gives you one point of accountability throughout. It is widely used for both commercial fit-outs and high-end residential projects.

Design and Build Cost Ranges in London (2026)

Luxurious living‑dining space with dark wood panel wall, beige and black sofas, green pillows, round marble coffee table with white flowers, large crystal chandelier, and an open view to a modern dining area with black chairs and geometric artwork. — Elegant blend of Art Deco geometry and rich textures in a contemporary lounge‑dining setting.

These are indicative ranges based on current London market rates:

Project Type	Cost Per Square Metre	Typical Total Range
Basic commercial fit-out	£500 – £800 psm	£50,000 – £150,000
Mid-range office design and build	£800 – £1,500 psm	£100,000 – £400,000
High-end commercial / hospitality	£1,500 – £3,000+ psm	£200,000 – £1,000,000+
Luxury residential design and build	£1,200 – £2,500+ psm	£150,000 – £600,000+

These figures include design fees, project management, materials, labour, and fit-out. They do not typically include VAT, structural engineering, or planning fees where applicable.

What Affects the Cost?

Modern open‑plan living space with white sofas, black coffee table and bar stools overlooking a city skyline at dusk through floor‑to‑ceiling windows. — Contemporary lounge with sleek white seating, black accents and an Art Deco‑inspired kitchen bar set against a dramatic city‑scape view at twilight.

Several factors will move your project budget up or down:

Specification level – The single biggest cost driver. The difference between mid-market and luxury finishes, flooring, joinery, lighting, and sanitaryware can double the per-square-metre cost.

Structural changes – If walls are coming down, services are being relocated, or there is any structural work involved, costs increase significantly. A straightforward cosmetic refurbishment is very different from a full renovation project.

Bespoke elements – Custom joinery, feature ceilings, specialist lighting design, and built-in furniture all add to the budget but often define the quality of the finished space. See our bespoke joinery and furniture design service for what is possible.

Programme and access – Fast-track projects or restricted access (phased commercial fit-outs, for example) often carry a premium due to out-of-hours working and compressed scheduling.

Location within London – Central London projects, particularly in the City or West End, typically cost more due to logistics, parking restrictions, and higher labour rates.

Is Design and Build More Expensive Than Using Separate Contractors?

Luxurious modern bedroom with wooden fluted wall panels, grey upholstered bed, circular accent chair, grey rug, recessed ceiling lighting and gold trim. — Elegant bedroom design featuring a grey upholstered bed, modern circular chair and warm wood accents with Mediterranean‑inspired lighting.

Not necessarily, and often it is more cost-effective overall. When design and construction are managed separately, gaps in communication and scope frequently lead to cost overruns. A single design and build company in London owns the full project, which reduces duplication, speeds up decisions, and limits the risk of costly mistakes.

For complex commercial interior design projects especially, the integrated approach consistently delivers better value at the end.

Get a Clear Budget From the Start

At Oraanj Interiors, we provide transparent cost guidance from the first conversation. There are no vague estimates, just honest, informed numbers based on your specific brief, site, and specification.