Office Refurbishment Cost in London: The Definitive 2026 Guide for Decision-Makers

By Servet Yuksel — BIID Registered Interior Designer, Founder of Kapeti Interior Architecture

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.

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 £400,000–£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. Read it once and refer back.

TABLE OF CONTENTS

1. The headline numbers: 2026 cost ranges by specification level

2. Defining your scope: refurbishment, CAT A, CAT B, and what each one costs

3. The complete cost breakdown — where every pound goes

4. Six factors that move your budget more than square footage

5. Hidden costs the typical fit-out quote omits

6. Sector-specific cost patterns: family office, finance, law, tech, professional services

7. Location premiums: Mayfair, St James's, City, Canary Wharf, Westminster, Knightsbridge

8. Heritage, listed and period buildings — when costs change category

9. Where the genuine savings sit — and where they don't

10. Three anonymised case examples — what real projects cost in 2026

11. How to read a fit-out quote without getting trapped

12. Programme: how long an office refurbishment actually takes

13. The five questions to ask any fit-out contractor before signing

14. Frequently asked questions

15. What to do next

1. THE HEADLINE NUMBERS: 2026 COST RANGES BY SPECIFICATION LEVEL

The single number most occupiers ask for — cost per square foot — is genuinely meaningful, but 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 refresh, minor partitioning	£35 – £65
Standard CAT B fit-out	Mid-market business, functional workplace, basic meeting rooms, moderate joinery	£75 – £105
Premium CAT B fit-out	Professional services, finance, investment management, bespoke joinery, integrated AV	£105 – £165
High-end CAT B fit-out	Family office, hedge fund, premium law firm, executive client suite, art-grade lighting	£165 – £250
Heritage / listed building	Georgian, Victorian, listed conservation area, specialist plaster, conservation joinery	£200 – £400
CAT A (landlord delivery)	Shell to ready-to-let standard, raised floor, ceiling, basic MEP	£55 – £95

A 5,000 sq ft office in central London therefore typically lands somewhere between £375,000 and £1,250,000 in construction cost depending on tier. Add 50–80% on top of that figure 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 £1.4–£2.5 million all-in.

These figures reflect what we are quoting and delivering in 2026. They are not aspirational. The London market has hardened materially since 2023 — labour, materials and landlord overlay costs are all up — and any guide quoting £45–£85 per sq ft as a realistic central London range is working with pre-2024 numbers.

Premium office refurbishment in central London — completed by Kapeti Interior Architecture, BIID registered design and build firm based in Chelsea

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

Three terms get used interchangeably in conversation. They are not the same thing, and confusing them is the most common reason cost expectations go wrong at brief stage.

CAT A (Category A) — The Landlord's Delivery

The shell fit-out a landlord provides before letting commercial space. Includes:

• Raised access floors (or screed where appropriate)

• Suspended ceilings or exposed soffit

• Basic perimeter heating, cooling and ventilation

• Standard LED lighting at minimum required levels

• Fire detection and basic life safety

• Toilets and base building services to lettable standard

Cost in central London 2026: £55–£95 per sq ftWho pays: The landlord, typically capitalised into the rentWhat you get: A blank, lettable shell. Not a working office.

CAT B (Category B) — The Tenant's Real Spend

Everything required to turn a CAT A shell into a finished workplace for a specific occupier. Includes:

• Internal partitioning and meeting rooms

• Reception, waiting area, 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 tierWho 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 ftWho pays: The occupierWhat changes: Cost depends almost entirely 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.

The Useful Reality

Most enquiries we receive labelled "refurbishment" turn out, after a proper site visit, to require partial CAT B treatment. Existing partitioning, MEP layout or finishes rarely support what the business actually wants the space to do at the next stage of its life. Plan for this honestly at brief stage and you will save 4–8 weeks of redesign cycle later.

3. THE COMPLETE COST BREAKDOWN — WHERE EVERY POUND GOES

This is the part of the office fit-out conversation that the rest of the market glosses over. Below is 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 cost	£ for 5,000 sq ft @ £130/sq ft
Strip-out, surveys, asbestos clearance	4%	£26,000
Partitioning, walls, doors, ironmongery	11%	£71,500
Mechanical and electrical (MEP) services	19%	£123,500
Ceilings, flooring, carpets, vinyls	9%	£58,500
Architectural and task lighting	7%	£45,500
Joinery: reception, kitchen, bespoke storage	14%	£91,000
Decoration, finishes, manifestation films	5%	£32,500
IT cabling, data, AV infrastructure	6%	£39,000
Glazing, internal partitions, manifestations	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 the figure a fit-out contractor will typically quote. It is not the all-in cost of getting your office finished and occupied. Several additional categories sit outside this number, covered in section 5.

What Drives the Largest Cost Categories

MEP services (19% of construction cost) — The single largest line item in any modern office fit-out. New offices need higher cooling capacity than offices designed even ten years ago, more power per workstation, more data points, more sophisticated lighting controls, more compartmentation for fire safety, and integrated mechanical extraction for tea points and meeting rooms. Cutting MEP scope to save money is the most reliably bad decision in this market — it produces a workplace that is uncomfortable for a decade.

Joinery (14%) — Reception counters, kitchen and breakout joinery, bespoke storage, banquette seating, integrated AV cabinets, feature ceilings. This is the category where specification tier swings cost most dramatically. Standard joinery from a UK supplier vs premium bespoke joinery can be a 60–100% cost difference for the same item.

Partitioning (11%) — Solid stud walls, glass partitioning, demountable systems, full-height acoustic glazing. Glass is meaningfully more expensive than stud (£200–£400/m² vs £110–£180/m²) and high-acoustic glazing is more expensive again. The decision to specify glass affects more than aesthetics — it dictates the cost trajectory of the whole project.

Preliminaries (10%) — The site overhead. Welfare facilities, waste removal, scaffolding, hoist hire, insurance, security, supervision time. Compressed programmes inflate this category. Difficult logistics in central London inflate it further.

Lighting (7%) — Architectural lighting, downlights, linear features, task lighting, dimming and control systems. A premium lighting design for a 5,000 sq ft office 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

Square footage is the easiest variable to talk about, but rarely the most important. In our experience delivering offices across Westminster, the City and Mayfair, six other factors swing the final cost more than the size of the floor plate.

1. Building Condition and Age

A 1990s post-war office block with original suspended ceilings, dated MEP and asbestos-containing materials in the soffit will cost meaningfully more to refurbish than a 2020 CAT A space in a contemporary building. Older buildings hide more — and asbestos surveys, strip-out, remediation, and unplanned structural discoveries all eat into the budget before any visible work begins.

A pre-2000 building should typically carry a 15–25% premium over modern stock for the same fit-out specification. A pre-1980 building carries a larger premium still. We find this discussion is missing from almost every fit-out cost quote a tenant receives, and is then introduced as "discoveries" once the project starts.

2. Floor Plate Complexity

A clean rectangular floor plate refurbishes faster and cheaper than a building with structural columns in awkward positions, low slab-to-slab heights, or curved external walls. London's older commercial stock — particularly in the City and parts of Westminster — has plenty of geometric quirks that add 5–15% to a fit-out budget for the same specification.

3. Specification Level

The difference between standard and premium specification can double the cost per sq ft without changing the floor area at all. Bespoke joinery, stone, premium lighting, acoustic panelling, integrated AV, hidden door details, art-grade plaster, custom-made door furniture — each category can be specified at three or four price tiers, and the total compounds quickly.

This is the category where most occupiers surprise themselves. A 5,000 sq ft office at £85/sq ft is £425,000. The same floor plate at £150/sq ft is £750,000. The change between those two specification levels is rarely about more space or more functionality — it is almost entirely about the quality of materials, the depth of joinery detail, and the calibre of lighting and AV.

4. Mechanical and Electrical Scope

Are you upgrading the cooling system? Adding cellular meeting rooms that need their own VAV boxes? Installing a fully integrated AV-conferencing solution across the whole office? Adding tea points with hot water and dishwashers on multiple floors? Installing acoustic glazing throughout? Adding additional power for trading screens, rendering workstations, or executive desks? MEP scope alone can swing a project budget by 15–30%.

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

5. Programme and Access Constraints

A 12-week programme costs more than a 20-week programme for the same scope, because compressed timelines mean overtime, multiple trades simultaneously, accelerated procurement, and premium-rate trades. Buildings with restricted out-of-hours access — common in mixed-use Westminster locations and most Mayfair listed buildings — drive cost up further.

A typical access premium for difficult West End buildings: 8–18% above the equivalent standard-access cost.

6. Landlord Requirements

Some landlords specify particular contractors for any work touching base building services. Some require their own MEP consultants to sign off design. Some demand that floor protection, hoarding and waste management hit very specific standards. Some impose mandatory programme reviews and gate procedures. Some require additional insurance levels or specific contractor accreditations.

In premium West End buildings the landlord overlay can add 8–15% to a fit-out cost, often without the tenant fully understanding why their numbers came in higher than the published market average.

5. HIDDEN COSTS THE TYPICAL FIT-OUT QUOTE OMITS

The construction quote you receive will not include all of the following. You should budget for them separately. This is where £400,000 quoted projects routinely become £600,000 actual projects.

Professional Fees

A properly designed office refurbishment requires several professional consultants:

Consultant	Typical 2026 Fee
Lead designer / interior architect	5–10% of construction cost
MEP consultant (if not in-house)	2–4% of construction cost
Building Control approval and inspections	£3,000–£10,000 fixed
Principal Designer (CDM 2015 — 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 cost

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 under one contract. (We are. Most of the market isn't.)

Furniture, Fixtures and Equipment (FF&E)

The chairs, desks, screens, workstations, soft furnishing, planters, kitchen appliances, AV equipment, signage, and artwork are almost always quoted separately from the fit-out construction. Realistic FF&E budgets in central London 2026:

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 (End of Lease)

If you are refurbishing leased office space, your lease almost certainly contains a dilapidations clause requiring you to return the space to a defined condition at the end of the term. The works you are about to commission directly affect that liability. Smart tenants negotiate dilapidations into their fit-out scope from day one. Many don't realise this until five years later when the schedule of dilapidations arrives.

A typical dilapidations liability on a 5,000 sq ft office in central London: £75,000–£200,000.

IT, AV, Security Hardware (Beyond Cabling)

Cabling is included in the construction quote. Servers, switches, access points, firewalls, AV control systems, video-conferencing endpoints, access control, CCTV, alarm systems — these are usually procured by the tenant separately, often through their own IT supplier. £12–£28 per sq ft is a realistic 2026 range for a finance or professional services environment.

Statutory Inspections, Certifications, Sign-Off

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

VAT

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

The Realistic Uplift From Construction Quote to All-In Cost

Pulling these together, the typical relationship between the construction quote you receive and the all-in cost of your finished, occupied office:

Cost Component	% of Construction Quote
Construction quote	100%
Professional fees	6–14%
FF&E	25–55%
IT/AV hardware	12–28%
Statutory and dilapidations strategy	8–20%
Subtotal pre-VAT	151–217% of construction quote
VAT at 20% applied to total	+30–43% of construction quote
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 a 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

Different sectors carry materially different cost profiles. The same square footage costs different amounts depending on what business is being delivered into the space.

Family Office and Wealth Management

Typical specification tier: Premium to high-endTypical cost range: £140–£220 per sq ft constructionDriving factors: Discreet client suite design, high-spec bespoke joinery, executive offices with acoustic isolation, integrated AV for client presentations, art-grade lighting, premium materials throughout, often in heritage or listed buildingsWhere the cost lives: Joinery (often 18–22% of construction cost vs 14% standard), MEP for acoustic isolation, premium finishesCommon surprises: Listed building consent requirements when located in St James's, Mayfair or Westminster Georgian buildings; bespoke joinery lead times of 12–18 weeks

Hedge Fund and Investment Management

Typical specification tier: PremiumTypical cost range: £130–£200 per sq ft constructionDriving factors: Trading floor power and cooling requirements, multiple secure meeting rooms, integrated technology, high specification reception, often dual-location resilience requirementsWhere the cost lives: MEP services (often 22–25% of construction cost vs 19% standard), IT and AV cabling, acoustic compartmentationCommon surprises: Power requirements that exceed base building capacity, cooling load calculations triggering additional MEP plant

Law Firm and Professional Services

Typical specification tier: Standard-Premium to PremiumTypical cost range: £105–£170 per sq ft constructionDriving factors: Multiple cellular offices, partner suite design, client meeting suite, library and document storage, secure file rooms, integrated AV in larger meeting roomsWhere the cost lives: Partitioning (often 14–17% of construction cost vs 11% standard), joinery for partner offices, acoustic glazingCommon surprises: Cellular office requirements triggering significantly more partitioning, MEP zoning, and door hardware than open-plan equivalents

Private Equity and Venture Capital

Typical specification tier: PremiumTypical cost range: £140–£190 per sq ft constructionDriving factors: Client-facing reception with brand presence, multiple meeting rooms with full AV, executive offices, sophisticated catering and breakout, reduced workstation count vs floor areaWhere the cost lives: Joinery, AV, lighting design, materials specification

Technology, Media and Creative

Typical specification tier: Standard to Premium (highly variable)Typical cost range: £85–£170 per sq ft constructionDriving factors: Open-plan layouts, breakout-heavy social space, brand-led design, sometimes warehouse or industrial conversion, often less hierarchical specificationWhere the cost lives: Brand-led joinery, lighting design, soft furnishings, AVCommon surprises: Acoustic strategy in open-plan environments — almost always under-specified, almost always regretted

Consulting and Audit

Typical specification tier: Standard-PremiumTypical cost range: £105–£150 per sq ft constructionDriving factors: Client-facing reception and meeting suite, balance of cellular and open-plan, premium AV in client-facing areas, agile workspace strategy

Investment Property and Real Estate

Typical specification tier: PremiumTypical cost range: £130–£185 per sq ft constructionDriving factors: Showcase reception, premium client-facing materials, demonstration of design competence to prospective tenants and investors, often in heritage buildings

A Note on Sector Bands

These ranges reflect what the upper-half of each sector typically commits to. Lower-end variants exist in every category, but they tend to deliver workplaces that feel materially below the calibre clients have come to expect. In our experience, the cost difference between a "sector-appropriate" and a "below-sector" specification is rarely more than 15–20%, but the perceived difference to staff and visiting clients is significant.

7. LOCATION PREMIUMS: HOW POSTCODE MOVES THE NUMBER

The same fit-out specification costs different amounts in different parts of London. The variation is real, and it is mostly explained by access, landlord standards, sector concentration, and surrounding building stock.

Mayfair (W1)

Typical premium over central London median: +15–30%Why: Class-leading client expectations, extremely tight servicing access, frequent listed building considerations, high concentration of family office, hedge fund and private equity tenants with non-negotiable specification standards, conservation area constraints throughout, narrow streets restricting deliveries, congestion charge and ULEZ compliance for all site vehiclesBuilding stock: Predominantly Georgian and Victorian period buildings; listed building consent required for many projects; conservation area designation across most of the districtServicing reality: Out-of-hours deliveries common, parking for tradespeople almost impossible, materials handling requires careful planningA 5,000 sq ft premium fit-out in Mayfair: £750,000–£1,100,000 construction cost realistic range

St James's (SW1)

Typical premium over central London median: +15–25%Why: Similar profile to Mayfair — family offices, private banks, traditional finance — combined with very high concentration of listed buildings and conservation requirementsBuilding stock: Georgian and Victorian; very high listed building density; consented schemes can require specialist contractors and 16–24 week lead times for design approvalA 5,000 sq ft premium fit-out in St James's: £700,000–£1,050,000

City of London (EC2, EC3, EC4)

Typical premium over central London median: +5–12%Why: Premium financial district stock with stringent landlord requirements, mandated MEP standards, controlled out-of-hours access, high standards for waste and noise managementBuilding stock: Mix of contemporary commercial buildings (less complex) and Victorian-Edwardian banking heritage (more complex); strip-out often constrained to weekends and overnightServicing reality: Generally easier than the West End; loading bays and dedicated service routes; weekend and night working common and accommodatedA 5,000 sq ft premium fit-out in City: £625,000–£925,000

Knightsbridge (SW1, SW3, SW7)

Typical premium over central London median: +12–20%Why: High specification expectations driven by premium residential and retail neighbourhood, frequent listed buildings, complex servicing, often part of mixed-use buildings with residential occupation requiring strict noise controlBuilding stock: Predominantly Victorian and Edwardian; Hyde Park Corner and Brompton Road area significant for office occupiers; conservation area constraintsA 5,000 sq ft premium fit-out in Knightsbridge: £700,000–£1,050,000

Westminster Core (SW1, WC1, WC2)

Typical premium over central London median: +5–15%Why: Mixed building stock from Georgian and Victorian commercial properties through to contemporary office blocks; logistics in central Westminster — particularly around Whitehall, Victoria, Pimlico and the Strand — variable; conservation area constraints in placesBuilding stock: Highly variable, from 1990s commercial buildings to listed period properties; Victoria area more uniform contemporary stockA 5,000 sq ft premium fit-out in Westminster: £625,000–£950,000

Canary Wharf (E14)

Typical premium over central London median: -5% to +5%Why: Modern stock, large floor plates, generous CAT A specifications, easier logistics, established occupier-fit-out cultureBuilding stock: Almost entirely contemporary new-build; high-rise; generous slab-to-slab heights; dedicated service infrastructureServicing reality: Loading bays, dedicated lifts, predictable access — significantly easier than central LondonA 5,000 sq ft premium fit-out in Canary Wharf: £575,000–£800,000

Holborn, Bloomsbury, Soho, Fitzrovia (WC1, WC2, W1)

Typical premium over central London median: +5–12%Why: Mixed contemporary and period stock, increasingly strong tech, media and consulting tenant base, generally good servicingBuilding stock: Mixed; Soho and Fitzrovia generally older stock with character; Holborn and Bloomsbury more uniform commercialA 5,000 sq ft premium fit-out in this band: £625,000–£900,000

South Bank, Shoreditch, Farringdon, Clerkenwell (SE1, EC1, EC2A)

Typical premium over central London median: Variable, -5% to +20%Why: Highly variable building stock; modern new-builds at the lower end, listed Victorian warehouse conversions at the top of the cost rangeTenant base: Strong creative, tech, media and consulting concentrationA 5,000 sq ft premium fit-out: £575,000–£950,000 depending heavily on building

Greater London (Hammersmith, Wimbledon, Stratford, Croydon)

Typical discount vs central London: -10–25%Why: Lower land cost, less constrained logistics, generally simpler buildings, lower labour and access costsA 5,000 sq ft premium fit-out: £450,000–£700,000

8. HERITAGE, LISTED AND PERIOD BUILDINGS — WHEN COSTS CHANGE CATEGORY

Listed buildings and period properties are not just "more expensive" — they 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, and the financial consequences are routinely underestimated at brief stage.

What Triggers Heritage Cost Treatment

• Listed Building status (Grade I, II*, II) — anywhere in the building

• Conservation area location — almost all of central London north of the Thames west of the City

• Pre-1850 construction

• Specific architectural features: cornicing, dado rails, panelled doors, sash windows, period flooring, original ceiling roses

• Party wall implications with adjoining listed properties

Why Heritage Costs Differently

Specialist trades. Listed building work requires craftspeople familiar with period techniques — lime plaster, traditional joinery, sash window restoration, parquet flooring matching, original cornicing repair. These trades cost meaningfully more per day than standard contractors and are in shorter supply.

Conservation officer engagement. Local authority conservation officers must approve material changes. This adds time (8–16 weeks for listed building consent) and cost (specialist heritage consultancy, design adjustments, sample submissions).

Reversibility requirements. Many listed building consents require interventions to be reversible — meaning bolted rather than fixed, surface-mounted rather than concealed. This affects MEP routing, partitioning fixings, joinery installation, lighting integration. It typically adds 10–25% to the cost of equivalent standard work.

Materials specification. Conservation requirements often specify particular materials matching original — lime mortar rather than cement, wide-board oak rather than engineered, traditional paints rather than modern emulsions. Materials cost rises significantly, lead times extend.

Surveys and documentation. Listed building consent applications require detailed measured surveys, photographic records, heritage statements, conservation method statements. Survey costs alone for a complex listed office can exceed £15,000–£30,000 before any design work begins.

Realistic 2026 Cost Premiums for Listed Buildings

Compared to standard contemporary commercial space at the same specification tier:

Listed Status	Typical Cost 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 CAT B fit-out specification, in a Grade II listed Mayfair Georgian office, can realistically run £170–£200 per sq ft for the same delivered output. The additional cost reflects the genuine specialist requirement, not contractor margin.

When Heritage Cost is Worth Paying

Heritage building occupancy is rarely accidental. Family offices, private banks, hedge funds, traditional law firms and high-end consultancies often 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. A BIID-registered designer with listed building experience and a heritage-trained build team will deliver a project that reads — to clients, staff, and visiting partners — as effortlessly correct. A contractor without that depth produces work that conservation officers reject, that staff find frustrating, and that the building eventually punishes through future remedial costs.

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

Cost-saving in office refurbishment is one of the most misunderstood topics in this market. Below is an honest account of what actually moves the needle and what reliably backfires.

Real Savings — These Matter

Design and build under one contract. When the same team is responsible for both designing and constructing the space, the coordination losses, redesign costs, and contractor change-of-scope claims that affect traditional procurement disappear. This alone typically saves 8–15% of total project cost compared to a designer-and-separate-contractor model. It also protects programme certainty, which has its own cost. (This is the model we operate at Kapeti — design, build, MEP coordination, joinery, decoration, FF&E procurement and project management, all under one contract, one programme, one liable party.)

Bespoke joinery produced through specialist manufacturers outside the UK. Reception counters, custom partitioning, integrated storage, banquette seating, feature ceilings, decorative joinery — these items have a cost structure where UK suppliers carry significant overhead, and where genuine specialist manufacturers in countries like Turkey, Portugal and Poland produce equivalent or higher-quality work at meaningfully better rates.

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

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

Early involvement of the build team. A tenant signs a lease, then engages a designer, then six weeks later engages a contractor, who then identifies a structural or MEP constraint that requires the design to change. That cycle is expensive, slow, and almost entirely avoidable by engaging the build team at brief stage. A design-build firm by definition removes this cycle.

Specification decisions made early and held. Most budget overruns we see in the market are not from unexpected site issues. They are from late-stage specification changes — joinery upgraded after design freeze, lighting specification changed mid-procurement, AV scope expanded after MEP installation. Each change has a multiplier effect on cost. Decisions made at design stage and held through delivery are the single most reliable cost-control discipline.

False Savings — These Usually Cost You

Choosing the cheapest fit-out quote. Almost every fit-out client who has ever experienced a serious cost overrun selected on lowest price. The variance you see between quotes is rarely about efficiency — it is about scope, specification, contingency and competence. Cheap quotes typically reveal exclusions and "provisional sums" three months into the project. Buying on price in office fit-out is the most reliably bad decision in this market. Section 11 covers how to read quotes properly to avoid this trap.

Cutting MEP scope. Inadequate cooling, undersized power, unfinished cabling routes, the wrong type of LED, no acoustic separation between meeting rooms — these are the things that make an office uncomfortable and unproductive for years. The savings from cutting MEP at design stage are tiny relative to the operational cost of a workplace that doesn't function.

Skipping the acoustic strategy. Open-plan offices without any acoustic thinking are a productivity disaster. Marginal cost of acoustic panelling, soft elements, separation glazing is small. Cost of not doing it is staff dissatisfaction and concentration loss that quietly damages performance for the duration of the lease.

Buying joinery off-the-shelf when bespoke is appropriate. Reception counters, kitchen fittings, executive office storage — when these are off-the-shelf, the office reads as off-the-shelf. The cost difference between specifying a standard reception and a properly bespoke reception is rarely more than £8,000–£18,000 on a project of any meaningful size. The visual and brand difference is enormous.

Reducing professional fees. Professional fees feel optional until something goes wrong. The cost of a properly engaged Principal Designer, MEP consultant or fire engineer is small relative to the cost of the project failing inspection, requiring remedial work, or generating insurance claims. CDM 2015 obligations are not optional, and a cheap appointment is genuinely worse than no appointment.

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

Below are three project profiles from our recent and current portfolio. Numbers are real ranges, anonymised at the request of the clients.

Case A — Investment Management Firm, Westminster

• Floor area: approximately 4,800 sq ft, single floor

• Building: Contemporary commercial building, 2010s construction

• Project type: Full CAT B fit-out, taking on a 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 design, custom acoustic ceiling treatment, glass and acoustic partitioning throughout

• Approximate construction cost: £620,000 (£129 per sq ft)

• FF&E: £195,000 (£41 per sq ft, premium specification across 35 workstations)

• Professional fees: Integrated under design-build, no separate consultant fees

• Programme: 14 weeks from contract signing to handover

• All-in completed project: Approximately £980,000 ex VAT

Case B — Family Office, Mayfair

• Floor area: approximately 3,200 sq ft across two floors of a Grade II listed Georgian building

• Project type: Refurbishment of an existing office. 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 throughout

• Approximate construction cost: £680,000 (£213 per sq ft)

• FF&E: £220,000 (£69 per sq ft, including specialist furniture commissions)

• Professional fees: Listed building consent advisory and fire strategy required separately, approximately £35,000

• Programme: 22 weeks across two phases, working around tenant occupation

• All-in completed project: Approximately £1.06 million ex VAT

Case C — Professional Services Firm, City of London

• Floor area: approximately 7,500 sq ft, two floors connected by a new internal staircase

• Building: Contemporary 2018 City office building

• Project type: CAT B fit-out of a CAT A shell. New internal staircase, eight meeting rooms, large reception, dedicated client suite, two breakout areas, partner offices and document storage zones

• Specification: Standard-premium. Restrained material palette, integrated AV across all meeting rooms, full MEP reconfiguration to support 80 workstations, bespoke joinery for reception and partner offices, acoustic glazing throughout

• Approximate construction cost: £790,000 (£105 per sq ft)

• FF&E: £245,000 (£33 per sq ft, mid-market specification)

• Professional fees: Building Control and Principal Designer fees, approximately £18,000

• Programme: 18 weeks

• All-in completed project: Approximately £1.16 million ex VAT

These are realistic 2026 numbers in the central London market. Anyone quoting you very different figures for similar scope is either delivering a different specification, working with pre-2024 cost data, or operating with an unsustainable cost structure that will resolve through variations during the project.

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

Most fit-out quotes look professional and contain the right line items. The problem is what they leave out, what they price as "provisional sums", and what they assume you have agreed elsewhere. Here is how to read one properly.

1. Identify the Assumptions Section

This is where the contractor protects themselves. 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 for new layout"

• "Excludes works to base building services"

• "Subject to access to all areas during normal working hours"

Each assumption is a potential cost increase if it doesn't hold. Before signing, work through every assumption against your actual building, lease, and landlord requirements. Convert assumptions into firm commitments wherever possible.

2. Identify Provisional Sums and Prime Cost Sums

These are placeholder budgets for items the contractor cannot price firmly at quote stage. Common ones in office fit-outs:

• Feature lighting

• Signage and manifestations

• Audiovisual equipment

• Bespoke joinery (sometimes)

• Carpet and flooring (if specification not yet finalised)

These will resolve to actual costs during the project — sometimes higher than the placeholder. If more than 15% of your total quote sits in provisional sums, you are signing a contract with significant budget risk. Push back. Ask for firm quotations on as much as possible before contract signing.

3. Examine the Exclusions List

Every fit-out quote excludes things — VAT, FF&E, IT equipment, telephony, security systems, dilapidations, professional fees beyond the contractor's own. Check the list against your assumptions of what the project covers. If something you expected to be included isn't, raise it before signing.

4. Verify the Contingency Provision

A fit-out quote without a contingency (or with a contingency below 5% of construction cost) is incomplete. Real projects encounter real surprises. Either the contractor builds 5–10% contingency into their quote, or you carry it externally on top of the quoted figure. Both are legitimate approaches; both are needed; one or the other must exist. A quote with no contingency is a quote that will exceed itself.

5. Examine the Programme

A quote with an aggressive programme will typically deliver an aggressive set of overtime claims and accelerated procurement charges. A quote with a realistic programme protects you. Be wary of contractors competing on programme — a 10-week programme for what should reasonably be 14 weeks usually indicates either inexperience or a deliberate underbid.

6. Examine the Payment Schedule

Front-loaded payment schedules (40% on signature, then back-loaded) are bad for the client. Stage-gate payments tied to deliverables are better. Watch out for "Application for Payment" mechanisms that allow the contractor to claim ahead of actual work completed. A reasonable payment structure: 10–15% deposit, monthly valuation against work completed, final 5% retained for 12 months post-completion.

7. Verify the Insurance and Accreditations

Every fit-out contractor should carry:

• Public Liability Insurance (minimum £5m, ideally £10m)

• Professional Indemnity Insurance (if they are providing design)

• Employer's Liability Insurance (statutory)

• Contractor's All Risks Insurance for the works

CHAS, SafeContractor, ConstructionLine accreditations are baseline. BIID, RIBA, RICS membership at the firm or principal level is a meaningful signal of competence. Ask for documentary evidence at quote stage. A contractor reluctant to provide insurance certificates is a contractor you should not engage.

12. PROGRAMME: HOW LONG AN OFFICE REFURBISHMENT ACTUALLY TAKES

Programme is one of the most consistently underestimated aspects of office refurbishment. Here are realistic 2026 timelines from contract signing to handover, exclusive of the design and pre-contract phase.

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

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

What Drives Programme Length

• Specification level (premium specifications require longer lead times for materials and joinery)

• Building access constraints (out-of-hours work extends programme)

• Procurement lead times for specialist items (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 in occupation

Compressing Programme Costs Money

A 5,000 sq ft premium CAT B fit-out compressed from a natural 16-week programme to a 12-week programme typically costs 8–18% more in overtime, accelerated procurement, multiple trades on site simultaneously, and premium-rate labour. If programme certainty matters more than cost (commonly true for businesses with hard lease commencement dates or client-facing launch deadlines), the compression is worth paying for. If both matter, the right answer is to start the procurement process earlier rather than to compress the construction phase.

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

A reputable contractor will have direct, comfortable answers to all five. Hesitation, evasion, or "we'll come back to you on that" on any of these is a meaningful signal.

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

Why it matters: These memberships represent professional accreditation and legal standing. CDM 2015 Principal Designer obligations are statutory for almost all commercial projects — a contractor without this capability is either not competent to deliver your project or is going to push the obligation back to you.

Good answer: "Yes — [specific accreditation], here is documentary evidence, and we deliver Principal Designer responsibilities in-house under CDM 2015."

Bad answer: "We work with consultants who handle that side."

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

Why it matters: As covered in section 11, provisional sums are placeholder budgets that can resolve higher than quoted. A quote with more than 15% in provisional sums carries significant budget risk.

Good answer: A specific percentage, with a list of which items are provisional and an explanation of why they cannot be firmed up at this stage.

Bad answer: Vague reassurances that "everything is included".

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

Why it matters: Real projects encounter real surprises. A quote with no contingency is a quote that will exceed itself.

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."

Question 4 — Can you show me three reference projects of similar scale and specification, with verifiable client contacts I can speak to?

Why it matters: This is the single best test of contractor competence. Anyone can produce a portfolio document. Almost no incompetent contractor can produce three clients willing to speak to a prospective customer.

Good answer: Three projects, three named contacts (with the contacts' permission), prepared to take a 15-minute call.

Bad answer: "We protect our clients' confidentiality" — when offered without an alternative validation route.

Question 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?

Why it matters: Programme certainty has commercial value. A contractor who takes liability for delays they cause is a contractor confident in their delivery. A contractor who has tracked their completion record is a contractor who manages programme as a discipline rather than a marketing claim.

Good answer: A specific programme, a clear position on liquidated damages or programme guarantees, and a 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 London market median for a standard CAT B fit-out in 2026 is £85–£105 per sq ft for construction cost only, plus FF&E (£18–£40 per sq ft), professional fees (6–14% of construction), and VAT at 20%. Premium central London locations and high-spec interiors run £140–£250 per sq ft construction cost. Heritage and listed buildings run higher still.

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

Standard CAT B: £75–£105 per sq ft construction cost.Premium CAT B: £105–£165 per sq ft.High-end CAT B: £165–£250 per sq ft.Heritage / listed: £200–£400 per sq ft.These are construction figures only. FF&E, professional fees, IT hardware, dilapidations and VAT are additional.

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

Standard specification: £2,000–£3,500 per workstation, or £18–£28 per sq ft.Premium specification: £3,500–£7,000 per workstation, or £28–£55 per sq ft.For a 50-person office at premium specification, FF&E alone runs £175,000–£350,000.

What hidden costs should I watch out for?

The five most commonly underestimated cost categories:

1. Professional fees — designer, MEP consultant, Principal Designer, Building Control, fire engineer. £40,000–£90,000 on most premium projects.

2. Dilapidations — what you'll owe at end of lease. Negotiate this into your fit-out scope from day one.

3. IT, AV, security hardware beyond cabling. £12–£28 per sq ft.

4. FF&E — usually quoted separately from construction.

5. VAT at 20% — applies to the entire project.

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

Six structural reasons: building age and condition, floor plate complexity, specification level expected by central London occupiers, MEP scope driven by modern occupier requirements, programme and access constraints in West End and City buildings, and landlord overlay requirements in premium buildings. Specification level 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 of an existing office, 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 you are in a listed building. Listed buildings, conservation areas, or any external alteration trigger additional consents. Allow 8–16 weeks for these processes if applicable.

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

If you lease your office, your lease almost certainly requires you to obtain landlord consent (a Licence to Alter) before carrying out any works that affect the structure, services or fabric of the space. Most fit-outs trigger this requirement. Securing the Licence to Alter is a process that runs in parallel with design and Building Control and typically takes 4–8 weeks in central London. Engage the landlord's surveyors early — delays here cost programme.

How long does an office refurbishment take in London?

Light cosmetic refresh (under 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.Premium CAT B (5,000–10,000 sq ft): 16–24 weeks.Listed building (any size): 22–36 weeks.Add 6–10 weeks at the front for design, statutory approval, and procurement.

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

In our experience, design-build is consistently 8–15% cheaper for total project cost on London office refurbishments under £1m. The reason is coordination cost: when design and build teams are separate, redesigns, contractor variations and programme slippage absorb the apparent savings of competitive contractor tendering. Design-build also protects programme certainty. For premium and heritage projects where specification quality matters, design-build also produces a more coherent end result because there is no handover between designer's intent and contractor's execution.

What is the difference between CAT A and CAT B?

CAT A is delivered by the landlord — raised floor, suspended ceiling, basic MEP, standard lighting, fire detection. £55–£95 per sq ft. The tenant inherits this when taking the lease.

CAT B is delivered by the tenant — partitioning, joinery, kitchen, reception, branded interiors, IT, AV, FF&E. £75–£250 per sq ft depending on specification. This is the major cost most tenants budget for.

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

Mayfair and St James's office refurbishment costs run 15–30% above the central London median for the same specification, driven by listed building density, conservation area constraints, restricted servicing access, and high client specification expectations. A premium 5,000 sq ft fit-out in Mayfair: £750,000–£1,100,000 construction cost. Listed Grade II premises add a further 20–35% on top of this.

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

City of London office refurbishments typically run 5–12% above the central London median, driven by stringent landlord requirements, mandated MEP standards, and out-of-hours access constraints — but usually below Mayfair/St James's pricing. A premium 5,000 sq ft fit-out in the City: £625,000–£925,000 construction cost.

Can I keep working in the office during the refurbishment?

Yes, with phased delivery — but it costs more. A phased refurbishment in occupation typically costs 40–80% more than the equivalent vacant-space programme, due to working hours restrictions, dust and noise management, multiple mobilisations, and reduced trade efficiency. For most occupiers, a planned temporary relocation or weekend/overnight working is more cost-effective than full continuous occupation during major works.

How do I keep my office refurbishment within budget?

Five disciplines consistently work:

1. Engage the build team early — at brief stage, not after a design has been completed in isolation.

2. Set a realistic programme — compressed timelines cost real money in overtime and accelerated procurement.

3. Make specification decisions early and hold them — most overruns we see come from late-stage specification changes.

4. Identify hidden costs at brief stage — professional fees, FF&E, dilapidations, IT hardware, VAT, all sized into the total project budget.

5. Choose a design-build partner with verified accreditation — BIID, RIBA, RICS, with documented insurance and demonstrable reference projects of similar scale.

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

Three reasons, in order of importance: scope differences (one contractor includes items the other excludes), specification differences (one prices premium, one prices standard, both call it "appropriate"), and provisional sum allocations (one places significant budget in placeholders, one prices firmly). Genuine efficiency or competence differences exist but rarely explain variances above 10%. 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

RELATED INSIGHTS

For occupiers considering specific aspects of their project:

• Office Fit-Out London: Design Decisions That Affect How Your Team Works → /post/office-fit-out-london-guide

• How Much Does a Restaurant Fit-Out Cost in London? → /post/restaurant-fit-out-cost-london

• Commercial Fit-Outs in High-Risk Buildings: Critical Decision-Making for Investors → /post/commercial-fit-outs-in-high-risk-buildings-critical-decision-making-for-investors

• Renovating in Knightsbridge & Mayfair: Licences, Building Management Rules, Contractor Pitfalls → /post/renovating-in-knightsbridge-mayfair-licences-building-management-rules-contractor-pitfalls-and

• How to Choose a Restaurant Fit-Out Contractor in London → /post/how-to-choose-restaurant-fit-out-contractor-london

• London Renovation for Turkish and Middle Eastern Property Owners → /post/london-renovation-turkish-middle-eastern-property-owners

SERVICE PAGES

• Office Fit-Out London — Service Page → /office-fit-out-london

• Commercial Interior Design London → /commercial-interior-design-london

• Design & Build London → /design-build-london

• Restaurant Fit-Out London → /restaurant-fit-out-london

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. Servet writes regularly on commercial interior design, fit-out economics, and the realities of London construction.