IN Brief:
- The Building Safety Regulator plans stronger scrutiny of subcontractor quality control on higher risk buildings.
- Main contractors will need effective supervision and evidence that approved designs are followed during construction.
- Gateway Three approval depends on demonstrating that completed work meets the regulated design and safety requirements.
The Building Safety Regulator is preparing to increase scrutiny of how main contractors supervise and control subcontractor work on higher risk buildings.
The regulator’s direction places greater emphasis on competence, inspection, accountability, and the quality systems used between Gateway Two design approval and Gateway Three completion. Main contractors remain responsible for demonstrating that construction follows the approved design and satisfies the building regulations.
Higher risk projects cannot treat specialist packages as isolated subcontract liabilities because electrical, fire, mechanical, structural, façade, and control systems interact throughout the building. A change within one package can alter the compliance or performance of several others.
Electrical installations carry extensive coordination requirements. Cable routes penetrate fire compartments, containment interfaces with structure and building services, distribution equipment requires access and ventilation, and life safety systems depend on verified supplies, segregation, controls, and commissioning.
The Building Safety Regulator has acted as the building control authority for higher risk buildings since October 2023. Gateway Two must be passed before relevant building work starts, while Gateway Three assesses the completed building and supporting information before occupation.
Work carried out on site must remain consistent with the approved design or progress through the required change control process. Informal substitutions, rerouted services, altered penetrations, or undocumented equipment changes can create substantial difficulties when the completed installation is assessed.
Stronger oversight is therefore likely to examine whether competence has been verified, supervision is proportionate, inspection points are defined, test results are retained, defects are closed, and changes are escalated before they become concealed within finished construction.
Evidence becomes part of the installation
A compliant physical installation without reliable records may still be difficult to demonstrate at Gateway Three. Test certificates, inspection reports, commissioning data, product information, drawings, photographs, change records, and sign offs need to correspond with the work actually installed.
Digital information systems can support this process, although software does not create quality by itself. Records must be generated at the correct stage, checked by competent people, linked to identifiable locations and assets, and protected from uncontrolled alteration.
Main contractors also need enough technical capability to challenge specialist work. Oversight cannot consist solely of receiving a completion certificate after the installation has been concealed.
Inspection plans should define hold points, witness testing, sample rates, responsibilities, and the conditions under which work can be energised or covered. Those controls need to be agreed before the programme reaches the relevant construction stage.
Electrical packages may require containment inspection before ceilings close, verification of fire stopping after cable installation, torque records for critical connections, protective device settings, discrimination studies, emergency supply tests, and integrated testing with fire, smoke control, lifts, access systems, and building management controls.
Competence must correspond with the task rather than remain a broad organisational statement. Design, installation, inspection, commissioning, and supervision require different knowledge, experience, and authority.
Temporary labour, labour only subcontracting, and layered subcontract chains can obscure responsibility unless roles are defined from the outset. The principal contractor must still know who carried out the work, who supervised it, and who accepted the evidence.
Parliamentary scrutiny of electrotechnical competence standards has also linked recognised skills with safety, employment practice, and the delivery of national infrastructure.
Quality control affects programme risk as well as regulatory compliance. Discovering a noncompliant cable route, penetration, or life safety interface before concealment may require limited remedial work, while finding the same issue during Gateway Three review can delay occupation and require destructive inspection.
Late value engineering, product substitutions, and compressed commissioning periods can introduce further risk. Any change must be assessed against the approved design, product performance, system coordination, and the building safety case before it is incorporated.
The regulator’s increased attention does not transfer responsibility away from specialist contractors. It reinforces the main contractor’s duty to control the complete project and ensure that subcontracted work is planned, supervised, inspected, and documented.
The practical response should begin before construction. Package interfaces, inspection and test plans, competence records, product approval routes, change procedures, and document workflows need to be established before work starts rather than reconstructed later.
Higher risk building compliance is moving towards a continuous evidence model in which approved design, site execution, inspection, change control, commissioning, and final records remain connected throughout delivery. Undocumented site decisions will be increasingly difficult to reconcile at completion.
