Office Fit-Out Procurement: Single Contractor vs Project Management

The two main routes

Commercial office fit-out procurement in London splits broadly between:

1. Single design-and-build contractor

   One firm takes responsibility for design, construction, M&E, commissioning and handover under a single fixed-price contract. The client has one contract, one point of contact, one invoice.

2. Traditional project management (PM route)

   Separate architect, M&E consultant, project manager and trade contractors. The client has 5–15 contracts. A PM firm coordinates.

A third, hybrid route — 'construction management' — exists but is less common in sub-20,000 sqft commercial fit-out.

Design-and-build — when to choose it

The design-and-build route works best where:

• Fit-out is under 15,000 sqft
• Programme certainty matters more than design bespokeness
• Cost certainty matters — fixed price from Day 1
• Client doesn't want to manage multiple contracts
• Timeline is compressed (under 16 weeks)
• The brief is clear and unlikely to change materially

Typical projects: mid-market CAT B, dilapidations, refurbishment, renovation. 80–85% of London commercial fit-out under 15,000 sqft goes design-and-build.

Advantages

• Single-point accountability — no finger-pointing between consultants and contractors
• Fixed-price certainty from design sign-off
• Faster programme — design and construction overlap
• Lower total fees — one margin, not multiple consultant fees
• CDM 2015 principal designer and principal contractor both in one firm

Disadvantages

• Design flexibility constrained — contractor's preferred subsystems influence design
• Bespoke high-end architecture harder to specify up-front
• Variation pricing harder to benchmark (no competitive tender)
• Requires trust in the contractor's design capability

Traditional PM route — when to choose it

The PM route works best where:

• Fit-out is over 20,000 sqft
• Design is architecturally ambitious or brand-led
• Multiple specialist design inputs required (AV, lighting, acoustic)
• Programme has flexibility to accommodate design-development phases
• Client has internal FM or construction management capability
• Competitive tender is required by governance

Typical projects: trophy HQ fit-outs, listed-building restoration, large multi-phase works.

Advantages

• Design control — architect reports to client, not contractor
• Competitive tender — trades priced against drawings
• Specialist input integrated (AV, acoustic, lighting, sustainability)
• Transparent cost breakdown — each trade priced separately
• Best for bespoke architecture

Disadvantages

• Higher total fees (architect + engineers + PM + contractor margin)
• Longer programme — sequential design, tender, construction
• Client carries coordination risk across multiple contracts
• Variations can arise from consultant-vs-contractor interface gaps
• More complex CDM 2015 appointments

Cost comparison — typical 10,000 sqft CAT B

Route	Total cost	Programme
Single D&B	£1.4M–£1.7M	14–18 weeks total (design + build)
Traditional PM	£1.5M–£2.0M	20–28 weeks total (sequential)

Difference is typically 5–15% on cost, 6–10 weeks on programme. The D&B route is cheaper and faster for most projects under 15,000 sqft.

Hybrid: design-and-build with client's architect

A growing middle route: the client appoints their own architect for design, then runs a D&B tender against the developed design. Contractor delivers 'to design'.

Benefits: architectural control + contractor delivery single-point. Downside: slightly higher total cost than pure D&B.

What we do

We self-deliver both design-and-build and 'contractor-only' routes. Full Office Fit-Out service is typically single-contractor D&B; we also deliver to client-appointed architect's drawings on a traditional basis.

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