A successful office renovation starts with the lease and the programme, not the design. A well-designed office delivered late, over budget, or with a reinstatement obligation nobody identified is still a failed project.
UK office fit-out costs in 2026 run from around £90 per square foot at basic specification to £190 and above at the top end, including construction, AV and furniture.
This guide follows the order a real project runs: lease, legal duties, surveys, design, programme, cost, delivery, procurement, handover. It covers England and Wales. Scotland and Northern Ireland have their own building standards and some different property laws.
Table of Contents
Start With the Lease, Not the Design
Write the brief first, and make it specific. “Accommodate 60 staff on a three-day hybrid pattern with eight meeting spaces and a client-facing reception” is a brief. “Modernise the office” is not, and the vagueness will reappear as variations.
Then read the lease. If you lease your premises, the lease decides what the project can be: what you may alter, whose consent you need, and what you must put back at the end. Designing first and reading the lease second is the most common and most expensive mistake in commercial fit-out.
Owner-occupiers have more freedom and a shorter decision chain, but carry the same regulatory burden. The section below is written mainly for tenants.
Your Lease: What You Can and Cannot Do
The alterations clause
Most commercial leases restrict alterations. Structural work is often prohibited outright. Non-structural alterations are usually permitted with the landlord’s written consent, which the lease will normally say cannot be unreasonably withheld.
Read it before briefing a designer. It tells you whether your scheme is achievable, needs adjusting, or needs a different building.
Licence to alter
A licence to alter is a formal written agreement between landlord and tenant permitting specific works to the premises. It attaches drawings and a specification, sets conditions on how the work is carried out, and records what happens at the end of the lease.
You will normally pay the landlord’s surveyor and legal fees as well as your own. Allow six to eight weeks, sometimes longer. Start the application while the design is still developing.
Dilapidations and reinstatement
Reinstatement is an easily overlooked end-of-lease cost.
Under most leases, alterations you make must be removed and the premises reinstated at the end of the term unless the landlord has waived that obligation in writing. Reinstatement obligations are absolute. Fair wear and tear does not apply to them.
In practice: stripping out partitions, removing raised floors, decommissioning supplementary air conditioning, making good every penetration, returning the space to base condition.
Negotiate reinstatement out before you build
Deal with this at the licence to alter stage, while the landlord wants your works to proceed and you still have leverage.
Ask for written confirmation of which elements must be reinstated and which the landlord will accept being left in place. A landlord expecting to re-let the space fitted will often waive reinstatement of partitions, floor boxes and air conditioning, because removing them destroys value they want to keep.
Get it in the licence, not in an email from a letting agent.
Cat A, Cat B and Refurbishment
Category A is the landlord’s base specification: raised floors, suspended ceilings, basic lighting, heating and cooling, fire detection, finished common parts. A usable but empty shell.
Category B is everything that makes the space yours: partitions and meeting rooms, kitchens and tea points, joinery, floor finishes, decoration, feature lighting, AV, data cabling, branding and furniture. Most tenant projects are Cat B, and most published cost benchmarks refer to it.
Refurbishing space you already occupy is the third case and often the most complex, because you are working around existing services, an existing layout and existing staff. Costs are less predictable, since what you find behind the ceiling drives the price.
Cat A is normally the landlord’s responsibility, Cat B yours. Any landlord contribution should be documented in the agreement for lease, with a clear mechanism for how and when it is paid.
CDM 2015: Your Legal Duties as the Client
Most businesses commissioning a refurbishment do not realise they are legally the client under the Construction (Design and Management) Regulations 2015, with duties they cannot delegate.
What the client must do
- make suitable arrangements for managing the project, proportionate to the risks
- appoint designers and contractors with the right skills, knowledge and experience
- allow adequate time and resources for each stage
- ensure welfare facilities are provided throughout
- provide pre-construction information to everyone designing or tendering
- ensure the principal contractor prepares a construction phase plan before work starts
- ensure the principal designer prepares and maintains the health and safety file
- maintain and review those arrangements for the duration of the project
How the work itself is planned and controlled is set out in the contractor’s method statements.
The appointment that matters
Where a project involves more than one contractor, and almost every office refurbishment does, you must appoint a principal designer and a principal contractor in writing.
If you do not make those appointments, the duties do not disappear. They fall to you.
When you must notify HSE
A project is notifiable using form F10 where construction work is scheduled to last longer than 30 working days and have more than 20 workers on site simultaneously at any point, or to exceed 500 person days in total. The client notifies HSE in writing and a copy is displayed on site.
The health and safety file
At completion you should receive a health and safety file covering anything a future project team would need to know. Keep it. You will be asked for it at the next refurbishment, and by any purchaser or incoming tenant.
Surveys Before Design
Design decisions made without survey information get changed on site, and changes on site are the expensive kind.
Asbestos. Any building constructed or refurbished before 2000 may contain it, and under the Control of Asbestos Regulations 2012 an asbestos register should already exist. Commission a refurbishment and demolition survey covering the areas you will disturb. Ceiling voids, risers, floor tiles, boiler flues and partition linings are the usual locations.
Measured survey. Do not design from the landlord’s marketing plan. Marketing areas and actual usable areas differ often enough to matter.
M&E condition. Assess incoming power capacity, distribution boards, air conditioning age, ventilation rates, fire alarm coverage and data infrastructure early. A project that discovers halfway through that the incoming supply cannot carry the new load is in serious trouble. Where service routes are unclear, a utility survey is cheaper than opening up.
Structure and voids. Check floor loading before specifying dense storage or server racks. Check ceiling void depth before specifying ductwork, and confirm the finished ceiling height you will be left with.
Space Planning and Design
Size for attendance, not headcount
Start with occupancy data. Since hybrid working became normal, most offices are sized for a peak attendance well below total staff, with a desk ratio somewhere between 0.6 and 0.8 desks per person.
Measure actual attendance for a month before fixing the space plan.
Acoustics
The most common complaint after a modern refurbishment is noise. Open plan without enough enclosed space produces a room nobody can concentrate in.
Provide a mix of bookable meeting rooms, small focus rooms for calls, and informal breakout space. Specify acoustic performance for partitions rather than assuming plasterboard will do it. A partition stopping at the suspended ceiling provides almost no separation; it must run to the soffit.
Accessibility
Approved Document M covers access to and use of buildings, and a refurbishment is the point to bring accessibility up to standard: level access, door widths, accessible WC provision, visual contrast, clear circulation. The Equality Act duty to make reasonable adjustments applies regardless of when the building was built.
Services and comfort
Daylight, lighting quality and air quality affect how a space gets used more than any finish. Specify LED lighting to appropriate lux levels with proper controls, and check ventilation rates against occupancy.
Where services are being reconfigured, price suspended ceiling work and integrated lighting as part of the package rather than as an add-on.
Building a Realistic Programme
The sequence
- Brief, budget and lease review
- Surveys and investigations
- Concept design and space plan
- Licence to alter application
- Detailed design and specification
- Tender and contractor appointment
- CDM appointments and construction phase plan
- Strip out
- Structural and builders work
- M&E first fix
- Partitions, ceilings and joinery
- M&E second fix
- Decoration and floor finishes
- Furniture and AV installation
- Commissioning, snagging and handover
Long-lead items set the date
The programme is dictated by whatever takes longest to arrive, not by how quickly trades can work. The usual culprits: switchgear and electrical distribution, air conditioning plant, glazed partition systems, bespoke joinery, task seating in specific finishes, and specialist AV.
Identify these at design stage and order early. A twelve-week lead item ordered in week ten of a twelve-week programme sets the completion date, whatever the contractor promises.
How long it takes
- under 2,000 sq ft: 4 to 8 weeks on site
- 2,000 to 10,000 sq ft: 8 to 14 weeks on site
- over 10,000 sq ft: 14 to 24 weeks on site
Add 8 to 16 weeks in front for design, consents and procurement.
Put float in the programme as well as the budget. Two weeks on a twelve-week project is realistic. A programme with no float will be late.
What It Costs in 2026
| Specification | Construction | AV | Furniture | Total |
| Low | £65 | £5 | £20 | £90 |
| Mid | £90 | £10 | £35 | £135 |
| High | £120+ | £15+ | £55+ | £190+ |
Figures are per square foot and weighted towards London. Regional markets including Nottingham and the East Midlands typically sit below these for construction and labour, though furniture, AV and specialist systems cost much the same everywhere.
For fuller breakdowns see our guides to office fit-out costs per square foot and office renovation costs in the UK.
What sits outside the headline rate
Professional fees and CDM roles. The landlord’s surveyor and legal fees for the licence to alter. Surveys, including asbestos. IT infrastructure, servers and telephony. Moving costs and temporary accommodation. Reinstatement liability at lease end. VAT.
Preliminaries and contingency
Preliminaries cover the cost of running the site: management, welfare, access, protection, waste, insurance and security. They rise sharply on occupied or out-of-hours projects.
Hold 10% contingency on a straightforward fit-out in a modern building, and 15 to 20% on a refurbishment of an older building where you cannot see behind the finishes.
Renovating While the Office Is Occupied
Phasing or decanting
Phasing works through the building in sections while staff remain. It avoids the cost of temporary space but typically extends the programme by 30 to 50% and raises preliminaries.
Decanting means moving out entirely and giving the contractor the whole floor. Faster, cheaper per square foot, and a better result, but you pay for temporary space.
For anything beyond light redecoration, decanting is usually the better economics once you price the extended programme and lost productivity of phasing.
Out-of-hours working
Noisy work in an occupied building generally has to happen outside working hours, which carries a labour premium plus additional supervision and security. Agree at tender stage exactly which activities are restricted and to what hours. Vague wording here produces claims later.
Noise, dust and fire escape
Core drilling, breaking out and fixing to structure are the loud activities; schedule them out of hours. Use temporary partitions and proper route protection for dust, and protect finished surfaces you are keeping, as covered in our guide to protecting flooring during construction.
Escape routes must remain available and adequately signed throughout. Any temporary change to means of escape needs assessing before it happens.
Tell staff the plan before work starts and update them weekly. Most disruption complaints on occupied projects are really communication complaints.
Procurement
Design and build or traditional
Design and build gives a single point of responsibility. The contractor takes on the design and delivers to a price. Faster, earlier cost certainty, and the sensible default for most SME office projects.
Traditional procurement keeps the design team separate and tenders a completed design. More control over detail, better suited to complex or heritage buildings, but slower and more exposed to variation risk.
What to check before appointing
- comparable office project experience, with references you actually call
- financial standing, checked at Companies House
- health and safety competence and capability to act as principal contractor
- insurances: public liability, employer’s liability, and professional indemnity on design and build
- the proposed team, including who will be on site day to day
- how they intend to manage an occupied building, if applicable
Our construction company checklist covers this in more detail.
Comparing tenders
Compare scope, not totals. Issue a common specification and a standard pricing document so every tender prices the same thing, then interrogate the differences.
The lowest tender is usually the one that excluded something: out-of-hours working, protection, waste removal, builders work in connection with M&E, or contingency for what is behind the ceiling. Those items reappear as variations once you are committed.
Contract
Use a recognised standard form appropriate to the value, such as JCT Minor Works or Intermediate. Agree the payment schedule against completed stages, a defects liability period, and any liquidated damages before signing. Avoid contractor’s own terms on anything significant.
Handover, Compliance and Sign-Off
Documents to receive before final payment
As-built drawings. Operation and maintenance manuals. Electrical installation certificates. Gas safety certification where applicable. Fire alarm and emergency lighting commissioning certificates. Air conditioning and ventilation commissioning records. Building control completion certificate where the work was notifiable. The CDM health and safety file. Warranties for installed systems and finishes.
Update your fire risk assessment
Under the Regulatory Reform (Fire Safety) Order 2005, the responsible person must review the fire risk assessment whenever there is a material change to the premises. A refurbishment altering layout, escape routes, compartmentation or occupancy is a material change.
This is a legal duty and it is routinely forgotten in the rush to move back in. Book the review before completion.
EPC and MEES
Energy performance. If ceilings, lighting and building services are already being opened up, assess energy-efficiency improvements at the same time rather than returning to them as a separate project later.
Snagging and defects
Walk the building with the contractor and produce a written snagging list at practical completion, with agreed timescales for closing it out. The defects liability period, typically six or twelve months, is your window to have faults corrected. Diarise a full inspection two to four weeks before it expires.
Measuring Whether It Worked
Set the measures before you start, or the project gets judged on the colour of the breakout sofa.
Track utilisation of desks, meeting rooms and focus space against the ratios you designed for. Survey staff before and after using the same questions, since noise, temperature and meeting room availability are the three that move. Check energy consumption per square metre, which should fall after any competent refurbishment. For owners, our guide to whether refurbishment increases commercial property value covers what moves valuation.
Common Office Renovation Mistakes
Designing before reading the lease. The scheme gets redrawn and the fees are paid twice.
Ignoring reinstatement. A liability that quietly builds from the day you finish.
Not making the CDM appointments. The duties land on you instead.
Sizing for headcount instead of attendance. Paying rent on space nobody uses.
Ordering long-lead items late. The completion date is set by the slowest delivery.
Underestimating occupied working. Phasing looks cheaper on paper and rarely is.
Comparing tender totals instead of scope. The gap is always an exclusion.
Partitions stopped at the ceiling. Looks like a wall, performs like a curtain.
Forgetting the fire risk assessment. A legal duty, missed in the move back in.
No contingency. Every older building has something behind the ceiling.
Office Refurbishment in Nottingham
An office refurbishment is a property project, a legal project and a construction project at once. The businesses that find it straightforward are the ones that sorted the lease and the programme before anyone picked up a pen.
Buon Construction delivers office refurbishment and commercial fit-out across Nottingham and the East Midlands, from single-floor refreshes to full strip-out and Cat B fit-out. We work to itemised specifications, take the principal contractor role, and can phase around an occupied building where that is the right answer. You can see the standard of finish in our recent projects, and our full range of services covers the trades involved.
To talk through your building, your lease and a realistic programme, get in touch.
