Commercial Design and Build in London: How It Works and What It Costs

Here’s how a commercial project goes wrong.

You appoint an architect. The drawings look good. You put them out to tender, three contractors price them, you take the middle one. Six weeks into the build someone opens a ceiling and finds the drawing doesn’t match the building. The contractor says he priced what he was given. The architect says the contractor should have surveyed it. Nobody is lying. Nobody is responsible either, and you’re the one paying for the meeting where this gets discussed.

Design and build exists because that gap costs money.

What design and build actually means

One contract. One company responsible for both the design and the construction.

You appoint a contractor early — often before the design is finished — and they take on the drawings, the structural engineering, the building control submissions and the build itself. If a detail doesn’t work on site, it gets solved inside the same team. There’s no gap to fall into, because there’s only one party holding the whole thing.

The traditional route splits it: designer first, contractor second, and a tender in between. That approach has its place. If you want absolute control over every specification and you have the time to develop the design fully before anyone prices it, traditional can suit you better. Design and build trades a degree of design control for speed and a single point of responsibility. Knowing which of those you actually need is the first decision worth making.

Most businesses we work with pick design and build for one reason: they need the space open and earning by a specific date.

Why businesses choose it

Speed is the honest answer. Design and construction overlap instead of running end to end. Groundwork and enabling works can start while the fit-out details are still being finalised. On a straightforward office or retail job that overlap alone can take four to six weeks out of the programme.

Cost certainty comes second. You get a fixed price against an agreed specification earlier than you would with a tender, and fewer of the variations that show up when drawings meet reality. Not zero variations — anyone promising that is selling something. Fewer.

Third, and least discussed: one phone number. When the electrician needs a decision about a wall that isn’t where the drawing says it is, that decision happens between two people who work for the same firm. You hear about it after it’s solved, not during.

The work we take on

Offices and fit-outs

Partitions, ceilings, lighting, data, air conditioning, kitchens and WCs. Sometimes a shell and core handover that needs everything; more often an existing floor that needs replanning around how people actually work now.

Most office work in London is general building plus services coordination. The services are usually what determines the programme, not the partitions.

Shops and retail

Retail runs to a different clock. There’s usually a trading date that can’t move, and often a landlord’s licence to alter that has to be agreed before anything starts. Shopfronts, flooring, lighting, back-of-house, and the electrical capacity to run all of it.

Bars and restaurants

This is the most technically demanding commercial work we do, and the least forgiving. Commercial kitchens need extraction, gas interlocks, grease management, and drainage that satisfies both building control and environmental health. Floors need to be right — resin in the kitchen zones, something that survives being mopped twice a day everywhere else. Acoustic separation matters if there are flats above, and in London there usually are.

We took The Cleveland Arms in Paddington from cellar to roof over roughly eighteen months: the pub at ground level, a new restaurant built into the basement, and three apartments on the floors above. The basement was the difficult part. It had been a beer cellar and a cold room, so it needed comprehensive damp-proofing, new concrete subfloors, structural steel to carry the building above, and pavement skylights waterproofed to a standard that has to work in the first bad winter, not the second. That project is written up in full as the Cleveland Arms renovation.

It was also a heritage building, which meant every façade decision — repointing, render, leadwork, the hand-painted signage — went through conservation guidance.

Small works and maintenance

Not everything is a fit-out. A lot of commercial work is a partition moved, a WC refurbished, a shopfront repaired after somebody reversed into it. We take these on, including reactive maintenance, because a contractor who only shows up for six-figure jobs isn’t much use when your extraction fails on a Friday.

How a project actually runs

Stage one: the survey nobody wants to pay for. We measure what’s there, open up where necessary, and find out what the building actually is rather than what the drawings claim. This is where the money is saved. Every unpleasant surprise found in week one costs a fraction of the same surprise found in week nine.

Stage two: design and specification. Layouts, services, finishes, and the structural work behind them. Our design team handles the drawings and the building control submission. If planning is needed — change of use, a new shopfront, anything external in a conservation area — this is when it goes in, and it sets the date everything else hangs off.

Stage three: pricing and programme. A fixed price against a written specification, and a programme with real dates on it. Read the exclusions. That’s where the honest and the optimistic quotes differ.

Stage four: build. Weekly site meetings, one point of contact, and written records of every decision that changes anything. Our pre-construction work covers the sequencing here — what order things happen in matters more on a commercial job than a domestic one, because you’re usually working around someone.

Stage five: handover, commissioning and the snag list. Certificates for gas, electrics and fire systems. Anything that runs — extraction, AC, alarms — gets commissioned and demonstrated, not just installed.

Working around a live business

This is the part clients worry about most and ask about least.

If you’re trading through the works, the programme has to be built around that from day one, not adapted later. That usually means phasing — half the floor at a time, or back-of-house first. It can mean night working, which costs more per hour but sometimes costs less overall because nothing stops. It means dust screens that actually seal, and a route for materials that doesn’t cross a customer’s path.

It also means agreeing the noisy work in advance and sticking to it. Breaking out a floor at eleven in the morning in a café is a good way to lose the client their regulars.

Landlords add another layer. Most commercial leases require consent for alterations, and the licence can take weeks. Start that conversation before you start pricing the job, not after.

What it costs

Commercial cost per square metre varies more than domestic work does, so a single figure would be misleading. What’s useful is knowing what moves it.

The specification moves it most — a basic office refit and a high-end restaurant can differ by a factor of three for the same floor area. Services come next: new extraction, added electrical capacity, air conditioning and drainage alterations are the items that turn a modest job into a substantial one. Then the building itself. A 1970s unit with generous risers is a different proposition from a listed Victorian building where every route has to be threaded through something protected.

Phasing and out-of-hours working add cost. So does a compressed programme; anything that needs to be finished faster than it naturally wants to be gets paid for somewhere.

We price against a written specification, with exclusions listed, because a quote that hides its assumptions is a variation waiting to happen. Come to us with a floor area and a rough intention and we’ll tell you the realistic range before anyone spends money on drawings.

Frequently Asked Questions

What is commercial design and build?

A single contract covering both the design and the construction of a commercial project. One company produces the drawings, handles structural and building control work, and carries out the build — so responsibility for the whole job sits in one place rather than being split between a designer and a contractor.

How is design and build different from traditional contracting?

In the traditional route the design is completed first, then tendered to contractors who price it. Design and build appoints the contractor early and overlaps the two stages. It’s generally faster and gives a single point of responsibility; traditional gives you more control over the detailed specification. Which suits you depends on whether your priority is the date or the detail.

How long does a commercial fit-out take in London?

A straightforward office or retail fit-out typically runs eight to sixteen weeks on site, with four to eight weeks of design and approvals beforehand. Restaurants and bars take longer because of kitchen services, extraction and licensing. A full multi-floor refurbishment can run well over a year — the Cleveland Arms took around eighteen months.

Can you work outside business hours?

Yes. Night and weekend working is common on retail and hospitality jobs where trading can’t stop. It carries a higher hourly cost but often shortens the overall programme and avoids lost revenue, so it’s worth pricing both ways before deciding.

Do you handle building control and licensing?

We handle building regulations submissions and coordinate structural approvals as part of the design and build package. Planning applications and change-of-use we manage too. Premises licences and environmental health registration stay with you as the operator, though we’ll build to the standards they require and provide the certificates.

What size of commercial projects do you take on?

From single-room alterations and reactive maintenance up to full multi-storey refurbishments. We’re a London contractor rather than a national one, so we take on work we can properly resource and supervise rather than everything that comes past.

Talk to us before the drawings

The cheapest hour on any commercial project is the first one, before anybody has committed to a layout. If you’ve got a lease to sign, a unit to fit out, or a building that needs to do something different from what it currently does, that’s the point at which a conversation is worth having.

Force Builders Ltd has been working across London for over 25 years, on commercial construction as well as residential. Call 077 6525 5189 and tell us what you’re trying to open, and when.