Cyclone Guide: Protecting Your Shed

What Is a Cyclone?

A tropical cyclone is an intense low-pressure weather system that forms over warm ocean waters. In Australia, cyclones typically occur between November and April and are known for destructive winds, heavy rainfall, and flying debris.

According to the Bureau of Meteorology, Australia experiences an average of 11 tropical cyclones each year, with 4–5 cyclones making landfall. The majority of these affect northern and coastal regions.

Cyclone Wind Regions in Australia

Australian buildings are designed according to AS/NZS 1170.2 – Wind Actions, which divides the country into wind regions based on cyclone risk:

• Region A – Non-cyclonic
• Region B – Intermediate cyclone risk
• Region C – Cyclonic (high risk)
• Region D – Severe cyclonic (extreme risk)

Why Region C Is High Risk

• Wind speeds can exceed 250 km/h
• Cyclones occur regularly, sometimes multiple times per season
• Buildings are exposed to extreme uplift and lateral wind forces
• Flying debris significantly increases damage risk

Sheds in this region must withstand repeated gusts, sudden pressure changes, and long exposure to severe winds.

How Cyclones Damage Sheds

1. Wind Uplift: High winds create suction forces that can lift roof sheets and structures if not properly engineered.
2. Internal Pressure: Wind entering through doors or openings increases pressure, which can cause structural failure.
3. Foundation Failure: Inadequate footings or anchoring can allow sheds to twist or overturn.
4. Flying Debris: Loose objects can strike walls and doors at high speed, causing breaches and collapse.

The Importance of Cyclone-Rated Sheds

A cyclone-rated shed is specifically engineered to withstand the wind speeds and forces expected in cyclone zones.

• Designed to AS/NZS 1170.2
• Use stronger steel, bracing, and connections
• Include certified fixings and anchoring systems
• Suitable for insurance and council approval

Non-rated sheds are not designed for cyclonic wind loads and are far more likely to fail.

Foundations and Anchoring Matter

Engineering data shows that many shed failures during cyclones occur due to poor anchoring, not weak steel.

• Concrete footings must meet engineering specifications
• Anchor bolts must be correctly installed and tightened
• Soil conditions must be considered in the design

Preparing Your Shed Before Cyclone Season

• Inspect bolts, brackets, and fixings
• Check doors and latches close securely
• Remove or secure loose items around the shed
• Look for corrosion, especially in coastal areas

Regular maintenance greatly improves cyclone performance.

During a Cyclone Warning

• Do not shelter inside a shed unless it is certified as a cyclone shelter
• Keep clear of sheds during peak winds
• Follow advice from local emergency authorities

Insurance and Compliance

Insurance claims may be reduced or denied if a shed does not comply with local wind region requirements.

• Meet Australian Standards
• Support insurance compliance
• Reduce long-term repair and replacement costs