Smoke Before Rain

There's a smell that arrives in North Queensland around this time of year, and everyone who lives here knows it without being told. It's the smell of cured grass burning somewhere out past the edge of town, a paddock off the Flinders Highway, a council hazard reduction burn on a ridge, a neighbour taking advantage of a still morning. By late afternoon the light goes soft and orange, the range gets hazy, and the sunsets turn spectacular for all the wrong reasons.

Ask anyone up here what the dangerous season is and they'll tell you cyclones. Fair enough. We've built an entire industry, a building code and a regional psychology around wind. But there's a quieter season that sits in the gap between the last dry month and the first real storm, and it runs from roughly now until the sky finally opens up in November. For about ten weeks, the thing most likely to test your shed isn't 200 kilometre winds.

It's grass.

The hazard we forget because it doesn't have a name

Down south, bushfire means forest. Tall timber, crown fires, days of it, the kind of thing that leads the national news for a fortnight. Up here it's a different animal entirely.

After a decent wet, the spear grass and buffel across the dry tropics can get chest-high or better. Then the dry season does what the dry season does: eight or nine months without meaningful rain, and by August that biomass has cured into something closer to kindling than pasture. What you get isn't a forest fire. It's a grass fire and a grass fire in cured spear grass moves fast, burns hot, and is often gone in less than a minute.

That last part is the bit that catches people out. A grass fire front can pass a building so quickly that the radiant heat never gets a chance to do serious damage to steel. The fire is over before it's really started. Nothing looks wrong.

And then, twenty minutes later, something inside the shed is on fire.

Steel doesn't burn. Sheds burn anyway.

Here's the honest version of a claim you'll see plastered across shed websites, including, in fairness, our own industry's marketing: steel is non-combustible. That's true, and it's not a small thing. Under the Australian bushfire construction standard, steel cladding and steel framing are compliant materials right up to the highest exposure levels. A Colorbond shed starts the fight with a genuine structural advantage that a timber-clad building simply does not have.

But steel sheeting isn't what burns down sheds. Embers are.

Embers are the primary ignition source in almost every bushfire loss, and they don't need a door left open. They need a gap. The standard is blunt about it: seal or screen anything two millimetres or larger, and use mesh with apertures under 2 mm where you need airflow. Two millimetres. That's less than the gap under a roller door that hasn't been adjusted in six years.

Once you start looking at a shed through that lens, you notice how many ways in there are:

• The ridge and barge lines, where profiled sheeting meets flashing and leaves a row of neat little corrugated openings unless it's filled or closed off.
• The base of the walls, especially where a slab has been poured slightly out of level and there's a hairline shadow of daylight along the bottom edge.
• Whirlybirds, wall vents and gable vents are great for heat, and a perfect intake for glowing debris if they're unscreened.
• The roller door, which is a large, deliberately imperfect seal by design.
• Translucent roof sheets and polycarbonate skylights, which behave very differently to steel under radiant heat.
• The gutters, holding a season's worth of dry leaf litter directly against the roof line.

And then there's the part nobody wants to talk about, which is what's actually stored inside. Hay. Diesel and jerry cans. Tyres. Timber offcuts. Aerosols on a shelf above the bench. A shed is a non-combustible box that we voluntarily fill with fuel. An ember through a 3 mm gap in a shed full of steel drums is an inconvenience. The same ember in a shed with half a tonne of hay in the corner is a total loss, and quite possibly a grass fire that starts again on the other side.

The 6-metre rule most people have never heard of

Worth knowing, because it surprises a lot of property owners: under both bushfire construction pathways, a shed or garage within six metres of a house has to be included in the house's bushfire design. Your shed isn't assessed in isolation. If you're in a designated bushfire-prone area and you're putting a garage close to the dwelling, that structure is now part of the building's fire performance and its Bushfire Attack Level assessment sits alongside the wind classification, not instead of it.

That's the point that matters most for anyone building this year. Cyclone rating and bushfire detailing are two different conversations. A shed can be beautifully engineered for wind tie-downs, bracing, footings sized for the site and still have a dozen unscreened openings. They're not the same question, and one doesn't answer the other.

What's actually worth doing in the next ten weeks

None of this needs to be dramatic. Grass fire preparation in the dry tropics is unglamorous and mostly involves a mower.

Mow a real buffer. Not a tidy strip. Cured grass right up to a shed wall means direct flame contact on the cladding and, more importantly, on every seal and gap in it. Slash it back properly and keep it back.

Clear the gutters, then clear them again. Late August leaf drop is real, and gutters are where embers land and settle.

Walk the perimeter at dusk and look for light. Stand inside with the doors shut on a bright afternoon. Any daylight you can see is an ember pathway. Mineral wool, closed-cell filler strips, corrosion-resistant mesh, or a proper flashing fix are all cheap, all a weekend job.

Stop stacking things against the outside wall. Pallets, firewood, old fence posts, the mulch pile. You've built a fuel bed against a steel wall and given the fire something to sit next to and radiate from.

Move the ignition sources away from the ignition points. Fuel drums and hay belong away from the roller door and the vents, not next to them.

If you're burning off, do it properly. In Queensland most fires over two metres in any dimension need a Permit to Light Fire from your local Fire Warden, and permits are cancelled the moment a local fire ban is declared. Check the Queensland Fire Department fire ban map before you strike a match, every single time. A permit is not a forecast.

Park facing out. Tractor, ute, slasher. If the day goes sideways you don't want to be reversing.

Then the rain comes

Here's the part that's always struck us as slightly absurd about building in this part of the world. We spend late August sealing gaps to keep glowing embers out of a shed, and by early November we're doing the identical work to keep horizontal rain from getting in. Same flashings. Same laps. Same 2 mm shadow line along the base of the wall. Same answer.

Fire, then water, ten weeks apart, and the detailing that solves one quietly solves the other. Which is really the whole argument for building properly the first time. A shed that's just a kit on a slab will let you know about it twice a year. A shed that's been detailed for the site, the wind, the grass, the storms, the ground it's actually standing on, will spend twenty years not being interesting, which is exactly what you want from a shed.

The smoke haze will hang around a while yet. Enjoy the sunsets, keep the slasher going, and check your gutters before the first storm rolls in off the ranges.

Planning a build before the wet? We're a family-run Townsville outfit, you'll deal with one person start to finish, and we're happy to talk through both wind and fire detailing for your site. Have a play with our shed design tool, or give us a call.