How to Quote and Run a Commercial Refurbishment Contract

What you will learn

• Why commercial refurbishment quotes need provisional sums and explicit scope exclusions to price risk accurately.
• How to structure a pre-start programme covering asbestos surveys, Building Regulations, and M&E checks before work begins.
• How to manage phased working in an occupied building without disrupting client operations.
• Why variation control in refurbishment requires a formal instruction register and written agreements from day one.
• What a properly structured refurbishment final account includes and how to close snagging without disputes.

Commercial refurbishment sits in different territory from new-build work. The building already exists, which sounds like it should simplify things - but existing buildings carry conditions that are invisible until walls come down, M&E that doesn't match any drawing, and clients who are often still operating on site. The contractor who wins a refurbishment contract and then discovers the HVAC system is fifteen years older than the survey suggested has a problem their quote didn't price for. This guide walks through how to survey, quote, programme, and close a commercial refurbishment contract without getting caught by those gaps.

Assess the Building Before You Quote

The most expensive mistake in commercial refurbishment is building a quote from a desktop exercise and a single short site visit. Refurbishment projects in older buildings routinely uncover asbestos, structural defects, or services in states that photographs don't capture. A proper pre-quote survey covers four areas.

Condition survey: Walk every zone with the client. Note existing finishes, ceiling condition, floor levels, and visible M&E services. Photograph everything - but also write a schedule of observed conditions, because photographs without commentary become ambiguous at dispute stage.

Asbestos: For any building constructed or refurbished before 2000, an asbestos survey is a legal requirement before notifiable work begins. The correct category for refurbishment work is a refurbishment and demolition (R&D) survey - distinct from a management survey. If the client has not commissioned one, make it a pre-condition of tendering or include it as a provisional sum.

M&E services review: Existing heating, ventilation, and electrical systems are the most likely source of budget surprises in any refurbishment. HVAC replacement can represent 15-25% of a full refurbishment's total project cost, and electrical upgrades - new distribution boards, cable runs, and testing to BS 7671 - can push the M&E element above 30% of total cost, according to ETS Group's 2026 commercial refurbishment cost analysis. An ageing but visible air conditioning system is rarely in good enough condition to survive integration into a refurbished building.

Planning and Building Regulations: Structural changes, change of use, and external alterations typically require planning permission. Internal refurbishments almost always require Building Regulations approval regardless. Establish which applies before quoting - finding out after contract award costs time that was not in the programme.

How to Structure the Quote

A commercial refurbishment quote fails when it is either too vague to hold or too specific to survive contact with the actual building. The right structure is explicit where scope is confirmed, and honest about what is not.

Scope narrative first: Before line items, write a clear scope of works narrative. State what is included and, critically, what is not. If existing kitchen units are being stripped out but not replaced, say so. If electrical systems are being reconfigured but not replaced, say so. Ambiguity at this stage becomes a dispute at final account.

Provisional sums for unknowns: For any item where the existing condition isn't fully confirmed - ceilings not yet opened, drainage not surveyed, structural condition pending an engineer's inspection - price as a provisional sum with the basis of calculation explained. A provisional sum is not a guess; it should reflect a realistic cost range for the most likely scenario, with a clear instruction process for converting it to actual scope.

Contingency: In commercial refurbishment, a contingency allowance is not optional. A contingency of 10-15% of the construction budget is recommended for most refurbishment projects; for buildings with limited survey access or incomplete condition records, price toward the higher end. Make clear in the quote that contingency is held separately and released by instruction, not automatically spent.

Cost per square foot as a sanity check: In 2026, a light commercial refurbishment runs roughly £40-£80 per square foot; a full refurbishment with M&E replacement £80-£150 per square foot; a high-specification Cat B fit-out £100-£200 or more - all construction costs only, before professional fees, surveys, and VAT. According to Zentura Workspace's 2026 refurbishment analysis, all-in project costs typically run 50-80% above the headline construction figure once professional fees (typically 3-7% of build cost), contingency, and VAT at 20% are added. When a client compares your refurbishment quote to an earlier fit-out-only estimate, they are usually comparing different scopes.

Programme and access conditions: State the working hours assumed, the access conditions required (out-of-hours working for occupied premises adds both cost and programme time), and the critical assumptions that underpin the price. If the project requires vacant possession before start and the building is currently occupied, make that a precondition of the contract, not a risk you absorb.

Pre-Start Requirements

Between contract award and start on site, a commercial refurbishment requires more preparation than most contractors programme for. Compressing this phase is where start-on-site dates slip before a single trade has arrived.

1. Confirm the asbestos R&D survey is complete, with a licensed removal plan for any identified materials. Licensed asbestos removal must precede any other works in affected zones.
2. Submit Building Regulations applications. For structural work, engage a structural engineer before submission. Standard full plans applications typically receive an acknowledgement within 5 working days, with approval following inspection stages.
3. Agree a phasing plan with the client if the building is occupied or partially occupied. Map which zones are handed over for works and when. Confirm the plan in writing - an occupied refurbishment managed informally becomes an occupied refurbishment managed by whoever shouts loudest.
4. Commission M&E surveys for any systems you are integrating with but not replacing. You need to understand the condition of what you are joining to before your works make you responsible for it.
5. Issue sub-contractor orders with programme obligations built in. Refurbishment projects are heavily dependent on trade sequencing - a drylining sub delayed by two days holds plastering, then decorating, then floor laying. Sub-contractor start dates and phase-completion milestones need to be contractual obligations, not advisory targets.
6. Establish a variation control process before works begin. Agree with the client who has authority to instruct variations, what format instructions must take, and what the pricing mechanism will be - daywork rates, schedule of rates, or lump-sum agreement per instruction. This is straightforward to agree pre-start and almost impossible to impose mid-project.

Running the Refurbishment Programme

The programme challenge in commercial refurbishment is that the building answers back. Every trade depends on a previous trade having finished, and partial occupation creates access constraints that rarely show up in the original programme.

Occupied buildings: When the client is still operating in part of the building, working patterns shift the programme in ways that headline dates don't show. Out-of-hours working for noisy or disruptive trades, daily dust suppression and site cleaning, and restricted access windows all add cost and time. These should be priced and programmed explicitly during the quote stage - a refurbishment delivered in a live building takes longer than the same scope delivered empty.

Coordination meetings: Weekly site meetings that include sub-contractor supervisors - not just your site manager reporting on their behalf - catch coordination issues before they become delays. If a glazing sub cannot confirm next week's access for partitioning because structural steelwork is not yet in place, that needs to be known on Monday, not Thursday.

Managing unknowns mid-programme: When walls come down and something unexpected is there - redundant services, structural elements not on drawings, materials not identified in the survey - your pre-start instruction process earns its value. Photograph the discovery, record the date, issue a variation enquiry to the client with cost and programme impact stated, and wait for a written instruction before proceeding. Verbal agreements about refurbishment variations are the most common source of unrecovered work in this sector.

Variation Control and Final Account

Variations are more frequent in commercial refurbishment than in new-build, because the existing building routinely differs from what the survey assumed. A contractor without a functioning change control process loses money on variations even when those variations are agreed in principle.

Instruction register: Maintain a live register of all variations and instructions from the first day on site. Each entry should record the date of instruction, who instructed it (name and confirmed authority), a brief scope description, and the status (priced, agreed, or disputed). The instruction register is your primary evidence document at final account - rebuilding it from memory or email threads at project end is slow and produces gaps.

Pricing variations promptly: A variation order priced and agreed quickly is worth significantly more than the same variation left to accumulate and negotiated at handover. Where you cannot price promptly because the scope is still being defined, issue a cost notice confirming that work is proceeding under instruction pending final pricing agreement. That notice creates a paper trail even when the number is not yet confirmed.

Final account structure: A commercial refurbishment final account typically includes the original contract sum, confirmed variation orders, provisional sum adjustments showing actual versus provisional costs, any contra-charges, and any agreed deductions for defects. Present it as a document that tells the story of the project clearly - not a list of line items without context. A well-structured final account reduces negotiation time because the client can follow the logic.

For contractors running multiple refurbishment contracts simultaneously, having all quotation versions, variation instructions, and stage invoices linked to a single project record matters more than on simpler contracts. Zigaflow's quoting and job management tools keep that documentation attached to the project, so the final account conversation starts from a shared record rather than two separate email trails.

Snagging and Handover

Snagging on a commercial refurbishment is more complex than on a residential project. The client may be re-occupying zones while others are still in progress, systems need commissioning and testing documentation, and compliance certificates need to be assembled from multiple sources.

Zone-by-zone snagging: If the building has been handed over in phases, maintain a separate snag list for each zone and close it against the zone handover date. A project-level snag list that merges issues from multiple zones is difficult to manage and easy to dispute.

Commissioning records: HVAC, lighting controls, and fire alarm systems must be commissioned, tested, and documented. Commissioning records are part of the handover pack required for Building Regulations sign-off. Missing commissioning documentation is one of the most common reasons a practical completion certificate is delayed.

O&M manuals and as-built drawings: The client needs documentation for every system installed or substantially altered. Collect this from sub-contractors throughout the project - chasing sub-contractors for O&M documentation after they have moved on to other jobs is slow and sometimes unsuccessful. Make document collection a condition of sub-contractor final payment.

Building Regulations completion certificate: Obtain and hand over the local authority completion certificate or approved inspector certificate at handover. Without it, the client has a building they cannot certify as compliant - and you have a final account that is harder to close.

Scope creep is the persistent risk in commercial refurbishment, and the counter to it is a documented scope from day one and a formal change control process that runs throughout. For a broader view of running a construction contract from award to settlement, see How to Run a Commercial Build Project: From Contract Award to Final Account. The same disciplines apply - commercial refurbishment simply tests them harder, because the building itself is the variable that new-build doesn't have.

Sources

• How Much Does an Office Refurbishment Cost? 2026 GuideZentura Workspace · accessed 2026-09-08
• Commercial Office Refurbishment Cost UKETS Group · accessed 2026-09-08

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