What to Expect During a Commercial Concrete Repair Project

Why Understanding the Process Reduces Anxiety and Improves Outcomes

Commercial concrete repair is a disruptive process. It involves noise, dust, vibration, access restrictions and temporary changes to the way a building is used — sometimes for weeks or months. For building owners, facilities managers and occupants who have not been through a concrete repair programme before, the uncertainty about what will happen, how long it will take and what disruption to expect is often as challenging as the disruption itself. This guide aims to give you an honest, practical picture of what a commercial concrete repair project looks like from commission to completion, so that you can plan your operations effectively, manage stakeholder expectations and make informed decisions at each stage of the process.

No two concrete repair projects are identical. The specific sequence, duration and disruption of works on your building will depend on its size, the extent of the defects, the access constraints, the specification of the repair materials and the agreed programme for phasing works around occupancy. What this guide describes is the typical process — the stages that almost all commercial concrete repair projects pass through, the decisions that need to be made at each stage, and the things that most commonly cause delays or cost increases when they are not anticipated at the outset.

MPS Concrete Solutions manages commercial concrete repair projects across all sectors in London and the South East. We are committed to transparent project communication and to working with building managers and occupants to minimise disruption while delivering a durable, compliant repair. Our Industrial Concrete Repairs service describes our scope, and our related guides — including How to Diagnose Concrete Defects and Concrete Spalling Repair Costs — provide context for the assessment and budgeting stages that precede the works described here.

Stage 1: Condition Survey and Specification

A properly managed concrete repair project begins not with a contractor on site but with a professional condition survey. The survey establishes the current state of the concrete — the extent of defects, their cause, their distribution across the structure and their structural significance — and is the foundation on which the repair specification and the programme are built. The survey is typically carried out by a structural engineer or a specialist concrete repair consultant, and it should precede any invitation to tender or contractor appointment. Attempting to price or specify a concrete repair project without a survey is the single most common cause of significant variations and disputes during the works, because the true repair extent is only established during break-out.

The condition survey for a commercial concrete repair project typically takes one to three days on site for a medium-sized structure (300–1,000 square metres of concrete surface area to be assessed), with a further one to two weeks for laboratory testing of samples, results analysis and production of the survey report and repair specification. The survey report should provide a crack map or repair map showing the location and extent of each defect area, the recommended repair principle and product system for each zone (referencing BS EN 1504 principles), and a quantified schedule of repair areas forming the basis for tender documentation. The cost of the survey and specification — typically £2,000–£8,000 depending on the structure's size and complexity — is a relatively small proportion of the total project cost and is invariably recovered by the value of information it provides during tendering and delivery.

Once the specification is issued, the project is tendered to a shortlist of specialist concrete repair contractors. A meaningful tender period of 2–3 weeks is appropriate for commercial repair projects, allowing contractors to visit site, review the specification and produce a detailed, itemised quotation. Single-quotation appointments without a survey or competitive tender — particularly common when a defect is discovered unexpectedly and there is pressure to resolve it quickly — frequently result in costs significantly above market rate and specifications that are not optimised for the specific defect type and structure. If urgency is genuine and time does not allow a full survey and tender process, consider appointing a contractor to provide a day-rate investigation and make-safe, followed by a properly specified and competitively tendered repair programme.

Stage 2: Pre-Contract Planning and Access Arrangements

Once a contractor is appointed, the pre-contract planning phase begins. This phase is less visible to the building manager than the physical works but is equally important to the outcome. It covers the production of method statements and risk assessments, the CDM notification and F10 submission where applicable, the procurement of materials (lead times for specialist repair mortars and injection resins can be 2–5 working days from order), the arrangement of plant and access equipment, the agreed programme of works and the stakeholder communication plan.

The most important planning task from the building manager's perspective is agreeing the access arrangements and the phasing of works. For occupied commercial buildings — offices, retail units, car parks, industrial facilities — works must be phased to allow the building's primary function to continue during the repair programme. This may mean restricting the contractor to specific working hours (7am–5pm Monday to Friday to avoid disruption to shift workers or residents), working in defined zones while other zones remain in use, restricting noisy percussive works to off-peak hours, or maintaining access to specific routes, lifts or parking areas throughout the programme. These constraints should be agreed in writing before works begin and should be reflected in the programme — a concrete repair programme produced without reference to the building's operational requirements is likely to cause more disruption than necessary.

Hoarding and containment requirements should also be agreed at this stage. Percussive concrete breaking generates significant dust, and appropriate containment — temporary hoarding, dust suppressants, HEPA vacuum extraction during grinding and cutting — is required both to protect occupants and to comply with the contractor's dust management obligations under COSHH Regulations. On healthcare sites and food production facilities, containment requirements are more stringent than on standard commercial sites, as described in our guides to Concrete Repair in NHS Hospitals and Concrete Repair in Food Manufacturing Facilities.

Stage 3: Site Works — Break-Out, Preparation and Repair

The physical works stage is where most of the programme, cost and disruption are concentrated. It follows a consistent sequence regardless of the repair type: substrate investigation and final repair mapping (which may differ from the survey map when the actual concrete condition is exposed during break-out); preparation of the substrate; application of the repair system; and curing and inspection. Understanding the sequence helps building managers anticipate what will be happening on site and what access restrictions will apply at each phase.

Break-out — the removal of deteriorated concrete to create a clean, sound substrate for the repair mortar — is the noisiest and most disruptive phase of the works. Depending on the repair area size and geometry, break-out may be carried out by hand-held percussive chisel, by pneumatic scaler, by hydrodemolition (high-pressure water jet) or by diamond saw cutting. Hand-held percussive tools generate impact noise in the range of 95–105 dB(A) at the tool; hydrodemolition generates somewhat lower structure-borne vibration but produces a large volume of dirty wastewater that must be contained and disposed of. The break-out phase may take from a single day (for a small number of point repairs) to several weeks (for extensive repairs across a large car park deck), and it is typically the phase that has the greatest impact on the building's occupants.

Following break-out, the exposed substrate — including any exposed reinforcement — is prepared and treated. This preparation includes cleaning and rust treatment of reinforcement (typically using a needle gun or wire brush, followed by application of a zinc-rich epoxy primer or migrating corrosion inhibitor), application of a concrete bonding agent to the substrate, and checking of the prepared surface profile against the specification requirement. The repair mortar is then mixed and applied according to the manufacturer's instructions and the specification, consolidated by hand or by vibration, and finished to the required profile. Curing of the repair mortar — protection from rapid drying, typically by polythene sheet or curing membrane for a minimum of 3 days — is critical to achieving the specified strength and durability and must not be abbreviated for programme reasons.

Stage 4: Protective Treatments, Quality Inspection and Handover

Once repair mortars have achieved adequate cure — typically 7–28 days depending on the mortar type and ambient temperature — the final protective treatment stage begins. On above-ground structures, this typically involves application of an anti-carbonation coating or a surface impregnant to the repaired and adjacent sound concrete areas, providing a barrier against further carbonation and chloride ingress. On car park decks and podium slabs, a full deck coating system (PMMA or polyurethane) is applied over the full deck area, typically following the sequence of primer application, reinforcing fabric at cracks and details, base coat, anti-skid aggregate broadcast, and topcoat. On basement structures, a cavity drain membrane or internal tanking system may be applied after the structural repair elements are complete.

At the end of the works — or at defined milestone stages for larger programmes — the contractor should carry out a formal quality inspection against the specification requirements. This inspection should include adhesion testing of the completed repair (pull-off testing to verify minimum bond strength), visual inspection of surface finish and profile, and verification that all documentation requirements have been met. A snagging visit, jointly conducted by the building manager or client representative and the contractor, should identify and resolve any outstanding items before the works area is handed back to the client. The contractor's quality assurance records — including material batch numbers, application dates, adhesion test results and any deviations from the specification — should be compiled into a handover pack provided to the building manager at practical completion.

MPS Concrete Solutions provides project-specific handover documentation for all commercial repair projects, including a summary of the works completed, the materials used and the quality assurance records. We also provide post-completion maintenance advice and, where appropriate, offer a planned maintenance visit 12 months after completion to inspect the repairs and protective coating system. If you are planning a commercial concrete repair project in London or the South East and would like to discuss our approach, contact our team to arrange a site visit and no-obligation assessment. Our guide to Concrete Structure Maintenance Programme describes how to maintain and extend the service life of repaired concrete elements after the project is complete.