Flue & chimney inspection across Greater Hobart.

The six-stage flue inspection.

1. Appliance collar inspection. Verify the appliance flue outlet is correctly sized for the flue diameter, gasket intact, mechanical join secure, no soot leakage at the collar.
2. Internal flue camera survey. Borescope or articulating camera fed up the flue, full visual record of the internal liner condition, any corrosion, sagging, soot accumulation, or partial blockage flagged.
3. AS/NZS 5601 clearance audit. Clearances to combustible materials (timber framing, plasterboard, ceiling lining) measured against the AS/NZS 5601.1 schedule for the appliance type and flue construction.
4. Terminal and cowl inspection. External terminal location, height above roofline, distance from openings, cowl condition, anti-downdraft features, screen mesh, bird and debris ingress.
5. Draft test. Manometer or smoke pencil at the draft hood with the heater firing — verify positive flue draft under normal and worst-case exhaust conditions.
6. Condition report. Photo record of each finding, AS/NZS 5601 compliance status, remediation recommendations with cost estimates.

The four common Hobart flue failures we find.

Corroded retrofit stainless liner in a heritage masonry chimney. Battery Point, Sandy Bay, South Hobart and West Hobart. A stainless steel liner dropped down an original masonry chimney 15–20 years ago to serve a converted gas heater. Acidic condensation in the cold cavity has progressively eaten through the liner wall — we routinely see pinhole corrosion, longitudinal splits and at the worst end, partial collapse. Replacement liner $900–$1,800.

Blocked terminal — nesting birds or accumulated debris. Most common on flues that haven’t been inspected in 5+ years. Hobart magpies, currawongs and starlings build nests in flue terminal cowls during the summer off-season. The nest is fine until the heater is fired up at the start of the next heating season — spillage, pilot extinguishing, CO risk. Inspection and terminal replacement $200–$450.

Insufficient clearance to combustibles. Found frequently in 1970s through 1990s installations where the original gas-fitter didn’t apply the AS/NZS 5601 clearance schedule rigorously, or where subsequent renovation work has placed timber framing or plasterboard inside the required clearance zone. Rectification varies from a heat-shield fit-out ($200–$400) to flue rerouting on a worst-case install.

Marginal flue draft on tight-sealed homes. Flue is physically sound but the house draws so little make-up air that the flue can’t establish a strong draft when the rangehood and bathroom fans are running. Remediation is either an upgraded H-cowl or anti-downdraft terminal ($350–$650), a fresh-air supply fitted to the room with the heater ($300–$700), or in worst-case scenarios a conversion to a sealed balanced-flue or fan-flued appliance.

Why tight homes change the flue calculation.

Older open-flued gas heaters rely on a thermal-buoyancy draft — hot combustion gases are lighter than the ambient air so they rise up the flue and pull fresh air into the appliance through the room. That works as long as the room can supply the make-up air. Hobart’s insulation, double-glazing and weather-sealing retrofits have dramatically reduced room infiltration. Add a modern kitchen rangehood pulling 600–1000 L/s on high setting and a bathroom exhaust fan, and the flue can quite easily reverse. This is a textbook scenario for the AS/NZS 5601 risk assessment and one we look for on every flue inspection in the inner-Hobart heritage suburbs.

Heritage chimney work in the City of Hobart.

Flue terminals, cowls and visible roof penetrations on Battery Point, parts of Sandy Bay and selected streets in South Hobart and West Hobart fall under City of Hobart heritage precinct rules. Any visible change needs Council heritage advisor sign-off. We hold the precinct contacts and routinely lodge submissions for discreet terminal options — usually a stainless terminal tucked behind the chimney pot rather than a visible cowl on the front roof plane. Adds a few weeks to the install timeline but avoids any compliance issue later.

Related services

Flue inspection is included in every full annual gas heater service. The standalone flue inspection is the right call when you’ve seen draft issues, soot deposits, or are preparing for a heater replacement. Where flue failure has caused spillage, the CO leak check is the safety follow-on. New flue installs and major rework fall under new heater installation.