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Defect library

Mechanical & electrical snags at handover

Mechanical and electrical services in commercial buildings need commissioning records and O&M manuals as well as working equipment. Many of these entries are about paperwork and labelling that should be in place before the client takes the building over.

Updated 19 October 2026

SiteSnag’s library has 11 entries under mechanical & electrical, and 1 of them are marked as safety or critical items. They’re listed below with the most serious first. Each one gives the wording an inspector would put in a report and the trade that would fix it, and 4 carry a reference to the standard or guidance they relate to. The references help you look up the relevant section and aren’t a statement that a particular home does or doesn’t comply.

All 11 entries

  1. Legionella risk (dead legs / TMV)

    Safety

    Dead legs or unserviced TMVs present a Legionella risk. Remove dead legs and service TMVs.

    Trade
    Plumber
    Reference
    HSE ACoP L8

  2. Air conditioning not working / leaking

    Major

    AC unit not cooling/heating or leaking. Investigate and repair.

    Trade
    Mechanical
    Reference
    None listed

  3. Fan coil condensate leak

    Major

    Condensate leaking from fan coil unit. Repair drain and replace damaged tiles.

    Trade
    Mechanical
    Reference
    None listed

  4. Ventilation not commissioned

    Moderate

    Ventilation air flows not balanced or commissioning records missing. Commission.

    Trade
    Mechanical
    Reference
    Approved Document F

  5. Lighting controls not working

    Moderate

    PIR/daylight/DALI lighting controls not working as designed. Commission.

    Trade
    Electrician
    Reference
    None listed

  6. Containment / cable tray not secured

    Moderate

    Cable containment unsupported or lids missing. Secure.

    Trade
    Electrician
    Reference
    BS 7671

  7. BMS not commissioned

    Moderate

    Building management system not commissioned or not reporting. Commission.

    Trade
    M&E contractor
    Reference
    None listed

  8. O&M manuals / test certificates outstanding

    Moderate

    Operation and maintenance manuals or test certificates not provided. Provide.

    Trade
    M&E contractor
    Reference
    None listed

  9. Plant room access / housekeeping

    Moderate

    Plant room cluttered, unlit or lacks safe access. Rectify.

    Trade
    M&E contractor
    Reference
    None listed

  10. Distribution board schedule missing

    Minor

    Circuit schedule missing from distribution board. Provide.

    Trade
    Electrician
    Reference
    BS 7671

  11. Services not labelled

    Minor

    Pipework, valves or isolators not labelled. Label to specification.

    Trade
    M&E contractor
    Reference
    None listed

Using these in a report

In the SiteSnag app, starting to type a defect title in the camera brings up these entries. Picking one fills in the description, severity, trade and reference, and you can edit the wording or add your own defects to the library. Every snag then goes into the branded PDF report with its photos and a numbered pin on the floor plan.

For a room-by-room walk-round, use the new build snagging checklist, or go back to all defect categories.

Other categories

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