Office Refurbishment Cost in London: The definitive 2026 guide for decision-makers

Servet Yuksel
1 day ago
20 min read

The headline number every London occupier needs to know:

A standard CAT B office refurbishment in central London costs £75–£140 per sq ft in 2026 for construction works alone. A premium fit-out in Mayfair, St James's or the City sits between £140–£250 per sq ft. Heritage and listed buildings reach £250–£400 per sq ft.

These are construction figures only. The all-in cost — including FF&E, professional fees, dilapidations and VAT — typically runs 50–80% higher than the construction quote your contractor presents.

This guide gives you the real numbers, the hidden costs the market doesn't discuss, and the six factors that move your budget more than square footage. Written by a BIID registered designer who has delivered offices, restaurants, hotels and high-end residential projects across Westminster, Mayfair, the City and Canary Wharf since 2019.

If you'd rather have a 30-minute conversation about your specific project than read 25 minutes, start a WhatsApp conversation with our team or email design@kapeti.com.

WHO THIS GUIDE IS WRITTEN FOR

This is not a generic article. It is written for a specific reader:

A founder, partner, finance director, COO, or executive assistant tasked with delivering a new office in central London
A family office, hedge fund, law firm, private equity firm, professional services firm, technology firm, or investment manager moving into or refurbishing prime central London space
Anyone who has been quoted £300,000–£2 million for an office fit-out and wants to understand what is actually behind the number
Anyone who has been told "every project is different — we can't give you a number" by a contractor, and wants the real benchmarks the industry uses internally

If that's you, the next 25 minutes will save you between £30,000 and £200,000 on your project.

1. THE HEADLINE NUMBERS: 2026 COST RANGES BY SPECIFICATION

The single number most occupiers ask for — cost per square foot — is meaningful only when separated by specification tier. Below are realistic 2026 ranges for central London office refurbishment, based on construction works only (no FF&E, no professional fees, no VAT).

Specification Tier	Typical Use Case	Cost per sq ft
Light cosmetic refresh	Existing office update, paint, carpet, lighting	£35–£65
Standard CAT B fit-out	Mid-market, functional, basic meeting rooms	£75–£105
Premium CAT B fit-out	Professional services, finance, bespoke joinery, integrated AV	£105–£165
High-end CAT B fit-out	Family office, hedge fund, premium law firm, art-grade lighting	£165–£250
Heritage / listed building	Georgian, Victorian, conservation joinery	£200–£400
CAT A (landlord delivery)	Shell to ready-to-let standard	£55–£95

A 5,000 sq ft office in central London therefore lands between £375,000 and £1,250,000 in construction cost depending on tier. Add 50–80% for the all-in completed project including FF&E, fees, dilapidations and VAT.

A 10,000 sq ft project in Mayfair or the City at premium specification commonly runs £1.2–£2.5 million all-in.

The London market has hardened materially since 2023 — labour, materials and landlord overlay costs are all up. Any guide quoting £45–£85 per sq ft as a realistic central London range is working with pre-2024 numbers.

For our broader commercial fit-out approach across office, restaurant, hotel and retail, see our Commercial Interior Design London service page.

2. DEFINING YOUR SCOPE: REFURBISHMENT, CAT A, CAT B

Three terms get used interchangeably. They are not the same thing.

CAT A — The Landlord's Delivery

Shell fit-out a landlord provides before letting:

Raised access floors or screed
Suspended ceilings or exposed soffit
Basic perimeter heating, cooling, ventilation
Standard LED lighting at minimum required levels
Fire detection and basic life safety
Toilets and base building services

Cost in central London 2026: £55–£95 per sq ft Who pays: Landlord, capitalised into the rent What you get: A blank, lettable shell. Not a working office.

CAT B — The Tenant's Real Spend

Everything required to turn a CAT A shell into a finished workplace:

Internal partitioning and meeting rooms
Reception and client-facing zones
Kitchen, breakout, tea points
Bespoke and standard joinery
Lighting design layered over base lighting
IT cabling, AV infrastructure, integrated technology
Branded interiors, signage, manifestations
Acoustic treatments
Decoration and finishes
FF&E coordination

Cost in central London 2026: £75–£250 per sq ft, depending on tier Who pays: The tenant. This is the major cost most occupiers budget for. What you get: A finished, occupied office.

Refurbishment — The Existing Occupier's Decision

Working with an existing, occupied or partially-occupied office to upgrade without a full vacate-and-rebuild cycle. Usually phased to keep the business running.

Cost in central London 2026: £45–£165 per sq ft What changes: Cost depends on how much existing infrastructure can be retained, and how much disruption is acceptable during works. Phased refurbishments cost more per sq ft than empty-space fit-outs of equivalent specification.

Most enquiries we receive labelled "refurbishment" turn out, after a site visit, to require partial CAT B treatment. Plan for this honestly at brief stage and save 4–8 weeks of redesign cycle later.

3. THE COMPLETE COST BREAKDOWN — WHERE EVERY POUND GOES

A realistic 2026 cost composition for a premium CAT B fit-out at £130 per sq ft, in a 5,000 sq ft office in central London:

Cost Category	% of construction	£ for 5,000 sq ft @ £130/sq ft
Strip-out, surveys, asbestos clearance	4%	£26,000
Partitioning, walls, doors, ironmongery	11%	£71,500
MEP services	19%	£123,500
Ceilings, flooring, carpets	9%	£58,500
Architectural and task lighting	7%	£45,500
Joinery: reception, kitchen, bespoke storage	14%	£91,000
Decoration, finishes, manifestations	5%	£32,500
IT cabling, data, AV infrastructure	6%	£39,000
Glazing, partitions	4%	£26,000
Project management, site supervision	6%	£39,000
Allocated contingency	5%	£32,500
Preliminaries (welfare, scaffold, waste, insurance)	10%	£65,000
Total construction cost	100%	£650,000

This is what a fit-out contractor typically quotes. It is not the all-in cost. Several categories sit outside this number, covered in section 5.

What Drives the Largest Cost Categories

MEP services (19%) — The single largest line item. Modern offices need higher cooling capacity, more power per workstation, more data points, sophisticated lighting controls, fire compartmentation, mechanical extraction for tea points and meeting rooms. Cutting MEP scope to save money produces a workplace uncomfortable for a decade.

Joinery (14%) — Reception counters, kitchen, bespoke storage, banquette seating, feature ceilings. Standard UK supplier vs premium bespoke can be a 60–100% cost difference for the same item. Our design and build approachroutinely produces 25–45% savings on this category through manufacturing partner relationships.

Partitioning (11%) — Glass is meaningfully more expensive than stud (£200–£400/m² vs £110–£180/m²) and high-acoustic glazing more expensive again.

Preliminaries (10%) — Site overhead. Welfare, waste removal, scaffolding, insurance, security, supervision. Compressed programmes inflate this. Difficult central London logistics inflate it further.

Lighting (7%) — Architectural lighting, task lighting, dimming and control systems. A premium lighting design for 5,000 sq ft is rarely below £40,000–£60,000 supply and install. Cheap lighting is the fastest way to make a £130/sq ft fit-out look like a £70/sq ft fit-out.

4. SIX FACTORS THAT MOVE YOUR BUDGET MORE THAN SQUARE FOOTAGE

1. Building Condition and Age

A 1990s post-war office block with original ceilings, dated MEP and asbestos-containing materials in the soffit costs meaningfully more to refurbish than a 2020 CAT A space. Pre-2000 buildings carry a 15–25% premium over modern stock for the same specification. Pre-1980 carries a larger premium still.

2. Floor Plate Complexity

Clean rectangular floor plates refurbish faster than buildings with awkward columns, low slab-to-slab heights, or curved external walls. London's older commercial stock adds 5–15% for the same specification.

3. Specification Level

A 5,000 sq ft office at £85/sq ft is £425,000. The same plate at £150/sq ft is £750,000. The change between these two levels is rarely about more space or functionality — it is almost entirely about quality of materials, joinery detail, and lighting/AV calibre.

4. Mechanical and Electrical Scope

Upgrading cooling? Cellular meeting rooms needing VAV boxes? Integrated AV-conferencing across the office? Hot water and dishwashers on multiple floors? Acoustic glazing throughout? Additional power for trading screens? MEP scope alone can swing a budget by 15–30%.

For finance, family office and hedge fund clients, MEP scope is almost always heavier than the baseline market assumes. A contractor quoting baseline MEP without flagging this is either inexperienced or hoping you won't notice until variation orders arrive.

5. Programme and Access Constraints

A 12-week programme costs more than a 20-week programme for the same scope. Out-of-hours restrictions in mixed-use Westminster locations and Mayfair listed buildings drive cost up: typical access premium 8–18%.

6. Landlord Requirements

Specified contractors, mandated MEP consultants, particular floor protection standards, programme reviews, additional insurance levels. Landlord overlay in premium West End buildings adds 8–15% to a fit-out cost, often without the tenant fully understanding why their numbers came in higher.

If you'd like a free 30-minute conversation about how these factors apply to your specific building, we run these site visits routinely.

5. HIDDEN COSTS THE TYPICAL FIT-OUT QUOTE OMITS

This is where £400,000 quoted projects become £600,000 actual projects.

Professional Fees

Consultant	Typical 2026 Fee
Lead designer / interior architect	5–10% of construction
MEP consultant (if not in-house)	2–4% of construction
Building Control approval	£3,000–£10,000 fixed
Principal Designer (CDM — legally required)	£4,000–£12,000 fixed
Fire engineer / fire strategy	£5,000–£18,000
Acoustic consultant (premium projects)	£4,000–£10,000
Structural engineer (if alterations)	£3,500–£15,000
Quantity surveyor (large projects)	1–2% of construction

For a £650,000 construction project, expect £40,000–£90,000 in professional fees beyond the contractor's quote — unless your contractor is a true design-build firm where these are integrated. (Kapeti is. Most of the market isn't.)

Furniture, Fixtures and Equipment (FF&E)

Specification	Per Workstation	Per sq ft
Standard	£2,000–£3,500	£18–£28
Premium	£3,500–£7,000	£28–£55
High-end / bespoke	£7,000+	£55+

A 5,000 sq ft office for 50 staff at premium specification carries £175,000–£350,000 in FF&E alone, beyond the construction quote.

Dilapidations

Your lease almost certainly contains a dilapidations clause requiring you to return the space to a defined condition at end of term. The works you commission directly affect that liability. A typical dilapidations liability on 5,000 sq ft in central London: £75,000–£200,000. Negotiate this into your fit-out scope from day one.

IT, AV, Security Hardware (Beyond Cabling)

Servers, switches, firewalls, AV control systems, video-conferencing endpoints, access control, CCTV. £12–£28 per sq ftfor a finance or professional services environment.

Statutory Certifications, Sign-Off

Building Control closure certificates, electrical certifications, gas certifications, fire risk assessment sign-off, BREEAM or SKA where required, party wall awards if applicable. £3,000–£15,000 in total, always there.

VAT

VAT at 20% applies to office refurbishment in almost all circumstances. 20% of £650,000 is £130,000, and many budget conversations forget this until the invoice arrives.

The Realistic Uplift From Construction Quote to All-In Cost

Cost Component	% of Construction Quote
Construction quote	100%
Professional fees	6–14%
FF&E	25–55%
IT/AV hardware	12–28%
Statutory and dilapidations	8–20%
Subtotal pre-VAT	151–217%
VAT at 20%	+30–43%
All-in completed project	181–260% of original construction quote

A £400,000 construction quote becomes a £725,000–£1,040,000 all-in commitment. This is not markup the market is hiding — it is structurally how commercial fit-out budgeting works. It is, however, almost never explained at the quote stage.

6. SECTOR-SPECIFIC COST PATTERNS

Family Office and Wealth Management

Typical range: £140–£220 per sq ft construction

Drivers: Discreet client suite, high-spec bespoke joinery, executive offices with acoustic isolation, integrated AV, art-grade lighting, often in heritage buildings

Common surprises: Listed building consent in St James's, Mayfair Georgian buildings; bespoke joinery lead times of 12–18 weeks

Hedge Fund and Investment Management

Typical range: £130–£200 per sq ft construction

Drivers: Trading floor power and cooling, secure meeting rooms, integrated technology, high-spec reception, dual-location resilience

Where cost lives: MEP (often 22–25% vs 19% standard), IT/AV cabling, acoustic compartmentation

Common surprises: Power requirements exceeding base building capacity, cooling load triggering additional MEP plant

Law Firm and Professional Services

Typical range: £105–£170 per sq ft construction

Drivers: Multiple cellular offices, partner suite, client meeting suite, library, secure file rooms, integrated AV

Where cost lives: Partitioning (14–17% vs 11% standard), joinery for partner offices, acoustic glazing

Common surprises: Cellular office requirements triggering more partitioning, MEP zoning, door hardware than open-plan equivalents

Private Equity and Venture Capital

Typical range: £140–£190 per sq ft construction

Drivers: Client-facing reception with brand presence, meeting rooms with full AV, executive offices, sophisticated catering, reduced workstation count vs floor area

Technology, Media and Creative

Typical range: £85–£170 per sq ft construction

Drivers: Open-plan layouts, breakout-heavy social space, brand-led design, sometimes warehouse conversion

Common surprises: Acoustic strategy in open-plan — almost always under-specified, almost always regretted

Consulting and Audit

Typical range: £105–£150 per sq ft construction

Drivers: Client-facing reception and meeting suite, balance of cellular and open-plan, premium AV in client areas

Investment Property and Real Estate

Typical range: £130–£185 per sq ft construction

Drivers: Showcase reception, premium client-facing materials, demonstration of design competence to prospective tenants and investors

7. LOCATION PREMIUMS: HOW POSTCODE MOVES THE NUMBER

Mayfair (W1)

Premium over central median: +15–30% Why: Class-leading expectations, tight servicing access, listed building considerations, family office and hedge fund concentration, conservation area throughout, narrow streets restricting deliveries A 5,000 sq ft premium fit-out: £750,000–£1,100,000

St James's (SW1)

Premium over central median: +15–25% Why: Family offices, private banks, very high concentration of listed buildings, 16–24 week design approval lead times A 5,000 sq ft premium fit-out: £700,000–£1,050,000

City of London (EC2, EC3, EC4)

Premium over central median: +5–12% Why: Stringent landlord requirements, mandated MEP standards, controlled out-of-hours access, strip-out constrained to weekends and overnight A 5,000 sq ft premium fit-out: £625,000–£925,000

Chelsea & Knightsbridge (SW1, SW3, SW7)

Premium over central median: +12–20% Why: High specification driven by premium neighbourhood, listed buildings, mixed-use buildings with residential occupation requiring noise control A 5,000 sq ft premium fit-out: £700,000–£1,050,000

For occupiers planning Knightsbridge or Mayfair projects, our guide on Renovating in Knightsbridge and Mayfair: Licences, Building Management Rules and Contractor Pitfalls covers the regulatory and operational realities in detail.

Westminster Core (SW1, WC1, WC2)

Premium over central median: +5–15% A 5,000 sq ft premium fit-out: £625,000–£950,000

Canary Wharf (E14)

Premium over central median: -5% to +5% A 5,000 sq ft premium fit-out: £575,000–£800,000

Holborn, Bloomsbury, Soho, Fitzrovia

Premium: +5–12% A 5,000 sq ft premium fit-out: £625,000–£900,000

South Bank, Shoreditch, Farringdon, Clerkenwell

Premium: Variable, -5% to +20% A 5,000 sq ft premium fit-out: £575,000–£950,000 depending on building

Greater London (Hammersmith, Wimbledon, Stratford, Croydon)

Discount vs central: -10–25% A 5,000 sq ft premium fit-out: £450,000–£700,000

8. HERITAGE, LISTED AND PERIOD BUILDINGS

Listed buildings exist in a different cost category entirely. Most of central London's prime office stock around Mayfair, St James's, Westminster and parts of the City sits in this category.

What Triggers Heritage Cost Treatment

Listed Building status (Grade I, II*, II)
Conservation area location
Pre-1850 construction
Specific architectural features: cornicing, dado rails, panelled doors, sash windows
Party wall implications with adjoining listed properties

Why Heritage Costs Differently

Specialist trades — Lime plaster, traditional joinery, sash window restoration, parquet matching, cornicing repair. Trades cost more per day and are in shorter supply.

Conservation officer engagement — Local authority conservation officers approve material changes. 8–16 weeks for listed building consent.

Reversibility requirements — Interventions often required to be reversible: bolted rather than fixed, surface-mounted rather than concealed. Adds 10–25% to equivalent standard work.

Materials specification — Lime mortar rather than cement, wide-board oak rather than engineered, traditional paints rather than modern emulsions. Materials cost rises, lead times extend.

Surveys and documentation — Measured surveys, photographic records, heritage statements. Survey costs alone can exceed £15,000–£30,000 before design work begins.

Cost Premiums for Listed Buildings

Listed Status	Typical Premium
Conservation area (not listed)	+5–10%
Grade II listed	+20–35%
Grade II* listed	+30–50%
Grade I listed	+40–70%

A £130/sq ft premium specification, in a Grade II listed Mayfair Georgian office, runs £170–£200 per sq ft for the same delivered output. The additional cost reflects the genuine specialist requirement, not contractor margin.

Heritage building occupancy is rarely accidental. Family offices, private banks, hedge funds and traditional law firms select Mayfair, St James's, Belgravia or City heritage buildings specifically for the address calibre and architectural character. The cost premium is part of the value proposition. If you're considering a listed building, send us a message — we deliver listed building work routinely and can talk through the planning and consent realities at brief stage.

9. WHERE THE GENUINE SAVINGS SIT — AND WHERE THEY DON'T

Real Savings — These Matter

Design and build under one contract. When the same team is responsible for design and construction, coordination losses and contractor change-of-scope claims disappear. 8–15% saving vs traditional procurement. Also protects programme certainty. This is how Kapeti operates as a design and build practice — design, build, MEP coordination, joinery, decoration, FF&E procurement, project management, all under one contract.

Bespoke joinery produced through specialist manufacturers outside the UK. Reception counters, custom partitioning, integrated storage, banquette seating, feature ceilings. UK suppliers carry significant overhead; specialist manufacturers in Turkey, Portugal and Poland produce equivalent or higher-quality work at meaningfully better rates.

The saving across our projects: 25–45% on the bespoke joinery line item, with no compromise on certification, fire rating, or quality control. Container shipping, customs and London installation factored in. We design in London, specify to UK standards, verify quality at production, manage shipping, install with our in-London team. The output is what the market delivers at £130/sq ft, delivered closer to £105.

Realistic programme planning. Compressed timelines cost real money in overtime, accelerated procurement, multiple trades simultaneously, premium-rate trades. Building 4–6 weeks of contingency in up front is one of the highest-return decisions a client can make.

Early involvement of the build team. A tenant signs a lease, engages a designer, six weeks later engages a contractor, who identifies a constraint requiring the design to change. That cycle is expensive and avoidable by engaging the build team at brief stage.

Specification decisions made early and held. Most overruns are not from unexpected site issues but from late-stage specification changes. Each change has a multiplier effect on cost.

False Savings — These Usually Cost You

Choosing the cheapest fit-out quote. Almost every cost overrun client selected on lowest price. Variance between quotes is rarely about efficiency — it is about scope, specification, contingency and competence. Cheap quotes reveal exclusions and "provisional sums" three months in.

Cutting MEP scope. Inadequate cooling, undersized power, wrong type of LED, no acoustic separation. The savings are tiny relative to the operational cost of a workplace that doesn't function.

Skipping the acoustic strategy. Open-plan offices without acoustic thinking are a productivity disaster. Marginal cost of acoustic treatment is small. Cost of not doing it is staff dissatisfaction for the duration of the lease.

Buying joinery off-the-shelf when bespoke is appropriate. Reception counters, kitchen fittings, executive storage. When off-the-shelf, the office reads as off-the-shelf. The cost difference is rarely more than £8,000–£18,000 on a meaningful project. The visual difference is enormous.

Reducing professional fees. Cost of a properly engaged Principal Designer, MEP consultant or fire engineer is small relative to the cost of project failing inspection, requiring remedial work, or generating insurance claims. CDM 2015 obligations are not optional.

10. THREE ANONYMISED CASE EXAMPLES — WHAT REAL PROJECTS COST IN 2026

Case A — Investment Management Firm, Westminster

Floor area: ~4,800 sq ft, single floor
Building: Contemporary commercial, 2010s
Project: Full CAT B fit-out on CAT A space
Specification: Premium. Bespoke reception with integrated joinery and stone, six cellular meeting rooms with full AV, two executive offices, premium kitchen and breakout, integrated lighting, custom acoustic ceiling, glass and acoustic partitioning
Construction cost: £620,000 (£129 per sq ft)
FF&E: £195,000 (£41 per sq ft, 35 workstations)
Programme: 14 weeks contract to handover
All-in: ~£980,000 ex VAT

Case B — Family Office, Mayfair

Floor area: ~3,200 sq ft across two floors, Grade II listed Georgian
Project: Refurbishment with tenant in occupation during phased works
Specification: Very high-end. Heritage-grade plasterwork restoration, bespoke handcrafted joinery throughout, integrated discreet security, art-grade lighting, restored period sash windows, conservation-approved materials
Construction cost: £680,000 (£213 per sq ft)
FF&E: £220,000 (£69 per sq ft, including specialist commissions)
Listed building consent and fire strategy: £35,000
Programme: 22 weeks across two phases
All-in: ~£1.06 million ex VAT

Case C — Professional Services Firm, City of London

Floor area: ~7,500 sq ft, two floors with new internal staircase
Building: Contemporary 2018 City building
Project: CAT B fit-out of CAT A shell. New staircase, eight meeting rooms, large reception, client suite, two breakout areas, partner offices, document storage
Specification: Standard-premium. Restrained material palette, integrated AV across meeting rooms, full MEP reconfiguration for 80 workstations, bespoke joinery for reception and partner offices, acoustic glazing throughout
Construction cost: £790,000 (£105 per sq ft)
FF&E: £245,000 (£33 per sq ft)
Programme: 18 weeks
All-in: ~£1.16 million ex VAT

These are realistic 2026 numbers in the central London market. If you'd like to discuss a project at any of these scales, start a WhatsApp conversation or email design@kapeti.com — first conversation is free.

11. HOW TO READ A FIT-OUT QUOTE WITHOUT GETTING TRAPPED

1. Identify the Assumptions Section

Common assumptions: "Subject to landlord agreement on hours of work", "Subject to no asbestos found in concealed areas", "Excludes out-of-hours premium rates", "Subject to existing electrical capacity being sufficient", "Excludes works to base building services". Each assumption is a potential cost increase if it doesn't hold.

2. Identify Provisional Sums and Prime Cost Sums

Placeholder budgets for items the contractor cannot price firmly: feature lighting, signage, AV equipment, bespoke joinery, carpet (if spec not finalised). If more than 15% of your total quote sits in provisional sums, you are signing a contract with significant budget risk.

3. Examine the Exclusions List

Every quote excludes things — VAT, FF&E, IT equipment, telephony, security systems, dilapidations, professional fees beyond contractor's own. Check the list against your assumptions.

4. Verify the Contingency Provision

A quote without contingency (or below 5% of construction cost) is incomplete. Real projects encounter real surprises. Either contractor builds 5–10% contingency in, or you carry it externally.

5. Examine the Programme

A quote with aggressive programme delivers aggressive overtime claims. Be wary of contractors competing on programme — a 10-week programme for what should reasonably be 14 weeks indicates either inexperience or a deliberate underbid.

6. Examine the Payment Schedule

Front-loaded schedules (40% on signature) are bad for the client. Stage-gate payments tied to deliverables are better. A reasonable structure: 10–15% deposit, monthly valuation against work completed, final 5% retained for 12 months post-completion.

7. Verify Insurance and Accreditations

Every contractor should carry:

Public Liability Insurance (minimum £5m, ideally £10m)
Professional Indemnity Insurance (if providing design)
Employer's Liability Insurance (statutory)
Contractor's All Risks Insurance for the works

CHAS, SafeContractor, ConstructionLine are baseline. BIID, RIBA, RICS membership is a meaningful signal of competence. A contractor reluctant to provide insurance certificates is a contractor you should not engage.

12. PROGRAMME: HOW LONG AN OFFICE REFURBISHMENT TAKES

Project Type	Floor Area	Realistic Programme
Light cosmetic refresh	Up to 3,000 sq ft	4–8 weeks
Standard CAT B	3,000–5,000 sq ft	10–14 weeks
Premium CAT B	3,000–5,000 sq ft	12–18 weeks
Standard CAT B	5,000–10,000 sq ft	14–20 weeks
Premium CAT B	5,000–10,000 sq ft	16–24 weeks
High-end CAT B	Any size	18–28 weeks
Listed / heritage	3,000–7,000 sq ft	22–36 weeks
Phased in occupation	Any size	1.5–2× equivalent vacant programme

Add 6–10 weeks at the front for design, planning, Building Control approval, Licence to Alter, procurement. A 5,000 sq ft premium CAT B fit-out from initial brief to occupation: 20–28 weeks total.

What Drives Programme Length

Specification level (premium = longer lead times)
Building access constraints (out-of-hours extends programme)
Procurement lead times: premium AV 8–12 weeks; bespoke joinery 8–18 weeks; specialist lighting 6–10 weeks
Statutory approvals: Licence to Alter 4–8 weeks; listed building consent 8–16 weeks
Single-phase versus phased delivery

Compressing Programme Costs Money

A 5,000 sq ft premium fit-out compressed from natural 16 weeks to 12 weeks costs 8–18% more in overtime, accelerated procurement, multiple trades simultaneously. If programme certainty matters more than cost (common for hard lease commencement dates), the compression is worth paying for. If both matter, start procurement earlier rather than compress construction.

13. THE FIVE QUESTIONS TO ASK ANY FIT-OUT CONTRACTOR BEFORE SIGNING

A reputable contractor has direct, comfortable answers to all five.

1. Are you BIID, RIBA, RICS or equivalent registered, and is your firm CDM 2015 compliant as Principal Designer?

Good answer: "Yes — specific accreditation, documentary evidence, we deliver Principal Designer responsibilities in-house under CDM 2015." Bad answer: "We work with consultants who handle that side."

2. What proportion of this quote is provisional sums or prime cost sums?

Good answer: A specific percentage, with a list of which items are provisional and why they cannot be firmed up. Bad answer: Vague reassurances that "everything is included".

3. What is your contingency provision and where does it sit in the quote?

Good answer: "5–8% of construction cost, allocated as line-item contingency, drawn down only against documented variations." Bad answer: "We don't include contingency — we just quote competitively."

4. Can you show me three reference projects of similar scale and specification, with verifiable client contacts?

Good answer: Three projects, three named contacts (with permission), prepared to take a 15-minute call. Bad answer:"We protect our clients' confidentiality" — offered without alternative validation.

5. What is your programme, what is your liability if it slips, and what is your record on completion dates over the past 24 months?

Good answer: Specific programme, clear position on liquidated damages or programme guarantees, willingness to share completion record data. Bad answer: Programme treated as best-efforts, liability avoided, no historical record offered.

14. FREQUENTLY ASKED QUESTIONS

What is the average cost of office refurbishment in London 2026?

The market median for standard CAT B in 2026 is £85–£105 per sq ft construction only, plus FF&E (£18–£40 per sq ft), professional fees (6–14%), and VAT at 20%. Premium central London locations run £140–£250 per sq ft construction. Heritage/listed runs higher still.

How much does a CAT B fit-out cost per sq ft in London 2026?

Standard: £75–£105. Premium: £105–£165. High-end: £165–£250. Heritage/listed: £200–£400. Construction only. FF&E, fees, IT, dilapidations, VAT additional.

How much should I budget for office furniture (FF&E)?

Standard: £2,000–£3,500 per workstation, £18–£28 per sq ft. Premium: £3,500–£7,000, £28–£55. For 50 staff at premium spec, FF&E runs £175,000–£350,000.

What hidden costs should I watch out for?

Professional fees (£40,000–£90,000 on premium projects)
Dilapidations (£75,000–£200,000 typical)
IT, AV, security hardware beyond cabling (£12–£28 per sq ft)
FF&E (usually quoted separately)
VAT at 20% on the entire project

Why is office fit-out so expensive in central London?

Six structural reasons: building age, floor plate complexity, specification level, MEP scope, programme and access constraints, landlord overlay. Specification and MEP scope are typically the largest single drivers — a 60–80% cost variance between standard and premium specification is normal for the same square footage.

Do I need planning permission to refurbish an office in London?

Internal refurbishment with no change of use and no external alteration does not typically require planning permission — but you will need Building Control approval, almost certainly a Licence to Alter from your landlord, and listed building consent if applicable. Allow 8–16 weeks for these processes.

What is a Licence to Alter and when do I need one?

If you lease your office, your lease almost certainly requires landlord consent (a Licence to Alter) before works affecting structure, services or fabric. Most fit-outs trigger this. Securing it typically takes 4–8 weeks. Engage the landlord's surveyors early.

How long does an office refurbishment take in London?

Light cosmetic (under 3,000 sq ft): 4–8 weeks. Standard CAT B (3,000–5,000 sq ft): 10–14 weeks. Premium CAT B: 12–18 weeks. Premium 5,000–10,000 sq ft: 16–24 weeks. Listed building: 22–36 weeks. Add 6–10 weeks for design, statutory approval, procurement.

Is it cheaper to hire a designer and a separate contractor, or use a design-build firm?

Design-build is consistently 8–15% cheaper for total project cost on London office refurbishments under £1m. Coordination cost — when design and build teams are separate, redesigns, contractor variations and programme slippage absorb the apparent savings of competitive tendering.

What is the difference between CAT A and CAT B?

CAT A: landlord-delivered shell — raised floor, suspended ceiling, basic MEP, standard lighting, fire detection. £55–£95 per sq ft. CAT B: tenant-delivered finished workplace — partitioning, joinery, kitchen, reception, branded interiors, IT, AV, FF&E. £75–£250 per sq ft.

How much does it cost to refurbish a Mayfair or St James's office?

Mayfair and St James's run 15–30% above central London median for the same specification, driven by listed building density, conservation constraints, restricted servicing, high client expectations. Premium 5,000 sq ft in Mayfair: £750,000–£1,100,000 construction. Grade II premises add 20–35% on top.

How much does it cost to refurbish an office in the City of London?

City runs 5–12% above central London median, driven by landlord requirements, mandated MEP standards, out-of-hours access constraints. Premium 5,000 sq ft in the City: £625,000–£925,000 construction.

Can I keep working in the office during the refurbishment?

Yes with phased delivery — but it costs more. Phased in occupation typically costs 40–80% more than equivalent vacant-space programme. For most occupiers, planned temporary relocation or weekend/overnight working is more cost-effective.

How do I keep my office refurbishment within budget?

Engage the build team early — at brief stage
Set a realistic programme
Make specification decisions early and hold them
Identify hidden costs at brief stage
Choose a design-build partner with verified accreditation

Why do office fit-out costs vary so much between contractors quoting the same project?

Three reasons: scope differences, specification differences, provisional sum allocations. Variances of 20–40% almost always reflect scope or specification differences, not contractor efficiency.

15. WHAT TO DO NEXT

If you are planning an office refurbishment in central London — whether you have just signed a lease in Mayfair, are reviewing options in the City, or considering refurbishing a Westminster heritage building — the most useful first step is rarely a detailed quote. It is a realistic conversation about what your space can become, what it will cost, and how long it will take.

We do this for free.

We will visit your property, walk through the brief, and give you genuine numbers and a realistic programme — usually within 48 hours of the visit. No commitment, no pressure, no follow-up sales calls if it is not the right fit.

Whether Kapeti turns out to be the right partner for your project or not, you will leave that conversation with a much clearer picture of where your budget needs to sit and what choices will produce the best result.

We are based in the Chelsea area, BIID registered, design and build under one contract, with a delivery team that has completed offices, restaurants, hotels, clinics and high-end residential projects across central London since 2019. We work directly with founders, partners, family principals, and senior decision-makers — not procurement intermediaries.

The first conversation is free. No cost, no obligation.

📲 WhatsApp: +44 7342 240695 ✉️ Email: design@kapeti.com 🌐 Website: kapeti.com

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Servet Yuksel is a BIID Registered Interior Designer and the founder of Kapeti Interior Architecture, a design and build practice based in the Chelsea area in London. Kapeti delivers offices, restaurants, hotels, clinics and high-end residential projects across central London for occupiers who value design quality and delivery certainty equally.