The wood heater arrives on a Thursday and sits in its carton for a fortnight. Nobody has worked out how the flue gets from the firebox, up through the ceiling, past a rafter and out through the roof without leaking. That last part — the flue flashing that seals where the pipe passes through the roof — decides whether you get a warm room or a water stain on the cornice.
This guide covers what a roof penetration for a solid-fuel heater, outdoor fireplace or wood-fired oven involves, and where a qualified installer takes over. It is deliberately not a step-by-step. A flue is a fire risk above the ceiling and a water risk below it, so the install belongs to a licensed roof plumber or an accredited solid-fuel installer. If you are still choosing the appliance, start with the heating range.
What a roof penetration actually involves
A flue penetration is not one hole. It is a hole through the ceiling lining, a clear path through the roof space, and a second hole through the sheeting or tiles. In between sit insulation, sarking, ceiling battens and — reliably — a rafter exactly where you wanted the pipe.
The installer has to keep combustible material away from a pipe that gets hot, and keep water out of a roof that now has a hole in it. Those goals pull against each other, which is why this is trade work. Ask for licence details and a compliance certificate before the job starts. Requirements vary by state and council, and some restrict new solid-fuel appliances altogether.
Flue flashing on a metal roof: what a Dektite does
On a steel or Colorbond roof, the standard answer is a moulded rubber flashing on a formable metal base. The Dektite Flue Flashing ($55) has a black EPDM cone on a square 432 x 432 mm base. That base is dressed down into the roofing profile, so the flashing follows the ribs rather than sitting proud of them.
Two numbers matter when you order. The rubber collar suits flues from 160 to 300 mm, and the EPDM handles a temperature range of minus 40C to 115C. Measure the outside diameter of your flue rather than quoting the nominal size, because the collar seals against the outer casing.
The parts of a flue run, from spigot to cowl
A flue run is a kit of parts, and the roof penetration is only one. Knowing the names makes a quote easier to read.
| Part | What it does | What to check |
|---|---|---|
| Flue pipe | Carries flue gases up past the roof line | Diameter must match the appliance's flue size |
| Bends | Steps the run around rafters and trusses | Bends add resistance; the installer decides how many |
| Roof flashing | Seals the penetration through the roof | Collar range and type must suit flue and roof |
| Ceiling ring, shielding | Keeps a hot pipe clear of lining and timber | Set by the appliance manual, never by eye |
| Cowl or cap | Terminates the run and keeps rain out | Chosen for the appliance and roof exposure |
Flue Pipe ($70) comes in 1,000 mm crimped lengths, so each slots into the next until the flue clears the roof line. Diameters run from 4 inch to 11 inch, in 304 stainless steel or galvanised steel, Australian made.
Runs rarely go straight up. Flue Bends ($71) step the pipe around framing: a pair of 45s offsets the run, a 90 turns it square. Telescopic stainless bends give an offset from 250 mm to 400 mm — the tidy fix when a rafter sits off your ideal centreline.
Metal, tile and the Australian roof reality
Most Australian houses give you one of two roofs, and they need different products. On steel sheeting, a Dektite-style flashing forms into the profile. On concrete or terracotta tiles the job changes: tiles come off, and a purpose-made tile flashing or a lead soaker tray is dressed into the courses around the pipe. Do not buy a metal-roof flashing for a tiled roof.
Two local complications come up constantly: sarking and reflective foil must be cut back and sealed around the penetration, and a roof crowded with solar panels can leave nowhere sensible to bring the flue out.
In bushfire-prone areas, councils and the state fire service may set extra requirements for the flue terminal and the appliance. On declared total fire ban days, restrictions can apply to solid-fuel appliances outdoors, and the CFA in Victoria, the NSW Rural Fire Service and Queensland Fire Department publish current rules. Our guide to patio heater safety basics covers the same ground for gas and electric units under a roofed alfresco.
The same thinking applies outdoors. A masonry fireplace or wood-fired oven under a roofed alfresco still needs its chimney taken through that roof, flashed and terminated clear of the structure. In the open you avoid the penetration entirely, which is why freestanding units from the fire pits and outdoor fireplaces range are simpler to add to a finished backyard.
Clearances belong to the installation manual
Clearances to combustibles — framing, plasterboard, decking, eaves, cladding — are set by the appliance's own installation manual and by the Australian Standard covering installation of domestic solid-fuel burning appliances, AS/NZS 2918. Every model is tested differently, so a figure that is right for one heater can be dangerous on another. Your installer reads the manual for your model, applies the standard, and sets the clearances, flue height and shielding.
The appliance's flue size is the one number you can plan around. The Eureka Amber ($2,700) lists a 150 mm flue, 12 kW output and coverage to 240 m², at 68% efficiency and 0.9 g/kg emissions. That flue size drives the pipe diameter, which drives the flashing collar.
After the install: sweeping and the winter check
A flue is not a fit-and-forget item. Creosote builds up inside the pipe, and a glazed or blocked flue is a leading cause of chimney fires. Sweeping before each burning season is standard advice, and mid-winter is a fair time to book next autumn's service. For the upkeep side of the job — reading what comes out of the pipe, doing the sweep and knowing when to hand it over — see our guide to flue cleaning for wood heaters.
Between professional inspections, the Flue Brushes Kit ($259) covers the sweeping. It has four 900 mm screw-together twist-wire handles in 8 gauge (4 mm) and a brush head with half-inch Whitworth fittings, so no UA1 adaptor is needed. The stocked head is 150 mm in diameter, matching the Eureka Amber's flue.
While the flue is being swept, have someone look at the flashing. EPDM hardens under years of UV, and a brittle collar lets water track down the pipe into the ceiling. Replacing it is a $55 part plus a roofer's morning — far cheaper than a ceiling.
Flue flashing and roof penetrations — frequently asked questions
Can I install flue flashing myself?
Treat it as installer work, not a weekend job. The flashing sits on a penetration that has to satisfy clearance rules for a hot pipe and weatherproofing rules for a roof. A licensed roof plumber or accredited solid-fuel installer should do both together.
What size flashing collar do I need?
Measure the outside diameter of the flue where it exits the roof. The Dektite's rubber collar suits 160 to 300 mm, and it seals against the outside of the pipe rather than the nominal flue size in the specifications.
How high does the flue have to go above the roof?
Your installer sets that height from the appliance's installation manual and AS/NZS 2918. It depends on roof pitch and where the penetration sits relative to the ridge, so no single figure suits every house. Ask for it in writing on the quote.
Does an outdoor pizza oven need a roof penetration?
Only if it sits under a roof. In the open, a freestanding fireplace or oven terminates in its own chimney. Under a roofed alfresco, that chimney has to pass through the roof, flashed and terminated the way a house flue would be.
Shop the range
Flue pipe, bends, flashings and brushes sit alongside the wood heaters in the heating range, so you can price the appliance and the run together. We deliver Australia-wide, delivery is free over $100, and most orders are dispatched in 3-10 business days. Installation is available on request.
