One of the first questions clients tend to ask when they approach us is brilliantly simple: “What will this actually cost?” It is a perfectly fair question to ask. The honest answer, however, is that design and build project costs across London vary considerably. It all depends heavily on the scope, the level of specification, and the sheer complexity of the work involved. Whether you are curious about how much it costs to renovate a house in the UK or planning a sprawling commercial workspace, having a realistic baseline is absolutely crucial.

That said, there are highly reliable benchmarks you really should know before you even start budgeting. Understanding what drives those numbers up or down will ultimately help you plan your finances with total confidence.

What Exactly Is a Design and Build Project?

Before diving straight into the costs, it is definitely worth clarifying what a design and build project actually entails. Unlike hiring an architect and a building contractor entirely separately, a design and build company seamlessly manages the entire process under one single contract. This covers everything from the initial creative concept and interior design right through to the physical construction, fit-out, and the final handover of the keys.

When evaluating design-build versus traditional contracting, you will find this single-contract model almost always reduces your personal risk. It significantly shortens project timelines and gives you just one clear point of accountability throughout the entire journey. It remains a highly favoured route for both complex commercial fit-outs and high-end residential overhauls.

What Are the Typical Design and Build Cost Ranges in London for 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 firmly on current London market rates. If your project is primarily focused on workspaces, you might also find it helpful to look into breaking down office fit-out costs to get a more granular view:

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+

Please keep in mind that these figures generally encompass design fees, dedicated project management, materials, labour, and the final fit-out. However, they do not typically include VAT, specialist structural engineering fees, or local authority planning fees where applicable.

What Actually Affects the Cost of Your Renovation or Fit-Out?

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 key factors will inevitably push your project budget either up or down:

Specification level – This is arguably the single biggest cost driver. The financial leap between mid-market and ultra-luxury finishes, premium flooring, bespoke joinery, intelligent lighting, and high-end sanitaryware can easily double your per-square-metre cost.

Structural changes – If solid walls are coming down, plumbing services are being drastically relocated, or there is any heavy structural work involved, costs will naturally increase significantly. A straightforward cosmetic spruce-up is vastly different from a full-scale renovation project.

Bespoke elements – Custom-built joinery, striking feature ceilings, specialist architectural lighting, and integrated built-in furniture all add to the initial budget. However, they almost always define the true quality and feel of the finished space. Have a look at our bespoke joinery and furniture design service to see what is genuinely possible.

Programme and access – Fast-track projects or sites with heavily restricted access (such as phased commercial fit-outs in occupied buildings) often carry a noticeable premium. This is usually due to necessary out-of-hours working patterns and highly compressed scheduling.

Location within London – Unsurprisingly, central London projects, particularly those nestled in the City or the West End, typically cost more. This accounts for tricky logistics, severe parking restrictions, and generally higher labour rates across the capital.

Is Design and Build Really 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 quite often, it proves to be far more cost-effective overall. When design and construction are managed entirely separately, frustrating gaps in communication and project scope frequently lead to expensive cost overruns. A single design and build company in London takes full ownership of the project. This severely reduces duplicated efforts, speeds up crucial decisions, and limits the terrifying risk of costly on-site mistakes.

For particularly complex commercial interior design projects, this heavily integrated approach consistently delivers far better value by the end of the build.

Are You Ready to Secure a Clear Budget From the Start?

At Oraanj Interiors, we fiercely believe in providing transparent cost guidance right from the very first conversation. There are no vague, fluffy estimates here—just honest, highly informed numbers based entirely on your specific brief, site condition, and desired specification.

Simply contact us to discuss your upcoming plans and secure a highly realistic budget for your next design and build project in London.