Post-Installation Checks: What the RC Must Verify
Once retrofit works are substantially complete, the Retrofit Coordinator (RC) has a critical responsibility to verify that installations meet PAS2035 requirements and the agreed specification. These checks form the gateway between construction and handover, protecting both occupant safety and retrofit performance claims.
Pre-Handover Inspection Protocol
The RC should conduct a systematic walkthrough of all retrofit areas before final sign-off. This involves:
- Checking that work scope matches the retrofit specification and design documentation
- Verifying all contractor sign-offs and quality records are complete
- Confirming safety-critical installations have been tested and certified
- Assessing workmanship standards against industry norms
- Recording any defects or incomplete works
This inspection should be documented with photographs and a detailed checklist. Where defects are found, issue a snagging list to contractors with clear timescales for resolution before final handover.
Thermal Insulation Verification
For insulation works, the RC must verify:
- Material specifications: Check delivery dockets and product certifications match the specification. Insulation type, thickness and thermal properties should align with design calculations
- Installation quality: Look for gaps, compression, settling or moisture damage. Insulation should be continuous across junctions and thermal bridges minimised
- Air tightness measures: Where required, verify that air barriers are properly sealed using appropriate tapes and membranes. Check junctions at walls, roofs, floors and service penetrations
- Ventilation adequacy: Confirm that ventilation provision (passive stack, mechanical extract or heat recovery) is correctly installed and unobstructed
Request thermal imaging reports where significant improvements are specified. These provide objective evidence that thermal bridging has been minimised and insulation is performing as intended.
Heating and Hot Water Systems
The RC should verify that heating and hot water systems are:
- Correctly sized according to the building's thermal load post-retrofit
- Properly commissioned with flow rates, temperatures and pressures logged
- Equipped with appropriate controls for heating zones and hot water temperature
- Fitted with thermostatic radiator valves (TRVs) where required by building regulations
- Connected to metering and monitoring equipment as specified
- Accompanied by manufacturer commissioning certificates
Request evidence that the system has been flushed and inhibitor added where applicable. For heat pumps, verify that outdoor units are positioned away from shade, prevailing winds and sensitive receptors, and that noise levels comply with local requirements.
Key point: Don't rely on contractor assurances alone. Physically inspect certification documents, test controls yourself, and request independent verification for critical systems like heat pumps or whole-house ventilation.
Ventilation and Air Quality
Retrofits often reduce uncontrolled air leakage, making mechanical ventilation essential. The RC must check:
- That intake and extract grilles are installed in the correct locations and unobstructed
- Ductwork is properly sealed and insulated to prevent condensation
- Heat recovery exchangers are clean and functioning
- Fan operation is audible (or silent for ultra-quiet units) and adjustable
- Controls are accessible and occupants understand how to adjust settings
Where passive ventilation is proposed, verify that stack ventilation relies on sufficient height difference and that background ventilators are correctly rated for the building's volume.
Water Safety and Legionella Risk
Hot water systems must be assessed for Legionella risk:
- Hot water must be stored at 60°C minimum and delivered at 50°C within 1 second at outlets
- Cold water storage temperatures should not exceed 20°C
- Pipework insulation should minimise heat loss and prevent stagnation
- Deadlegs (redundant pipe sections) should be removed or flushed regularly
Request a Legionella risk assessment from the installer, particularly where hot water storage or complex distribution pipework is involved.
Electrical and Controls Installation
Verify that:
- All electrical work is certified by a qualified installer and meets Building Regulations
- Smart controls are properly configured and occupants have received training on operation
- Metering equipment is functioning and transmitting data as expected
- Emergency controls and overrides are accessible and clearly labelled
Building Fabric Inspection
External envelope works require particular attention:
- Render, cladding or weatherproofing is properly finished with no cracks or water ingress
- Window and door installations are sealed and draught-proofed
- Roofing membranes are continuous and properly sealed at penetrations
- External inspection chambers and service connections are protected from water ingress
Documentation and Handover
Before signing off, ensure the RC receives:
- All manufacturer warranties and guarantees
- Commissioning certificates and test reports
- Operating and maintenance manuals for key systems
- As-built drawings and the updated Building Logbook
- Post-retrofit SAP assessment and energy performance certificate
- Copies of all installer qualifications and insurance certificates
Schedule a formal handover meeting with the building owner or occupants to walk through new systems, controls and maintenance requirements. This reduces future performance complaints and supports long-term retrofit success.
Post-installation verification is not bureaucracy—it's the mechanism that ensures retrofit investments deliver the intended benefits safely and reliably.