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Defect library

Heating defects in new builds

Heating faults are easier to find in winter, when the system is running, so turn the heating up during the inspection and feel each radiator. Ask for the boiler commissioning paperwork as well, because it should be handed over with the house.

Updated 19 October 2026

SiteSnag’s library has 15 entries under heating, 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 8 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 15 entries

  1. Flue terminal position unsafe

    Safety

    Flue terminal too close to an opening or boundary. Investigate and correct.

    Trade
    Heating engineer
    Reference
    Approved Document J

  2. Boiler not commissioned / fault

    Major

    Boiler shows fault or commissioning record not provided. Commission and provide certificate.

    Trade
    Heating engineer
    Reference
    Gas Safe

  3. Gas safety certificate missing

    Major

    Gas Safe certificate or boiler commissioning record not provided. Provide.

    Trade
    Heating engineer
    Reference
    None listed

  4. Open fire / stove certificate missing

    Major

    No HETAS or installation certificate for stove or fire. Provide.

    Trade
    Heating engineer
    Reference
    None listed

  5. Radiator cold / not heating

    Moderate

    Radiator does not heat up. Bleed and balance system, check valves.

    Trade
    Heating engineer
    Reference
    NHBC Standards 8.1

  6. Radiator loose on wall

    Moderate

    Radiator is not securely fixed to the wall. Re-fix brackets.

    Trade
    Heating engineer
    Reference
    NHBC Standards 8.1

  7. Heating controls not working

    Moderate

    Thermostat, programmer or zone valve not working. Repair and set up.

    Trade
    Heating engineer
    Reference
    None listed

  8. Underfloor heating zone not working

    Moderate

    Underfloor heating zone not heating. Investigate manifold/controls.

    Trade
    Heating engineer
    Reference
    None listed

  9. Heat pump noisy / not performing

    Moderate

    Heat pump excessively noisy or not reaching set temperatures. Investigate and recommission.

    Trade
    Heating engineer
    Reference
    None listed

  10. Boiler pressure low / losing pressure

    Moderate

    Boiler loses pressure. Find leak, repair and re-pressurise.

    Trade
    Heating engineer
    Reference
    NHBC Standards 8.1

  11. Radiator valve leaking

    Moderate

    Radiator valve or tail weeping. Tighten or replace.

    Trade
    Plumber
    Reference
    NHBC Standards 8.1

  12. Missing radiator valve cap

    Minor

    Valve head/cap missing from radiator. Fit missing part.

    Trade
    Heating engineer
    Reference
    NHBC Standards 8.1

  13. TRV missing / not working

    Minor

    Thermostatic radiator valve missing or stuck. Fit/replace.

    Trade
    Heating engineer
    Reference
    None listed

  14. Radiator needs bleeding / airlocked

    Minor

    Radiator cold at top or system airlocked. Bleed and re-pressurise.

    Trade
    Plumber
    Reference
    NHBC Standards 8.1

  15. Thermostat poorly located

    Minor

    Room thermostat in a draught, by a heat source or not reachable. Relocate.

    Trade
    Heating engineer
    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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