If you’re building or renovating in or near bushland, you’ll hear the term “BAL rating” early. It affects what materials you can use, what your build will cost, and how well your home stands up to a bushfire.
What is a BAL rating?
A BAL (Bushfire Attack Level) rating measures how much bushfire exposure a building site could face. It’s based on radiant heat, ember attack, and direct flame contact. The rating decides the minimum construction requirements under Australian Standard AS 3959, Construction of buildings in bushfire-prone areas. A higher BAL means a higher risk, which means stricter rules for materials like cladding, eaves linings, windows and doors.
What are the six BAL levels?
There are six levels, from lowest to highest risk:
- BAL-LOW: Very low risk. No specific bushfire construction requirements.
- BAL-12.5: Low risk. Protects against ember attack and minor radiant heat (up to 12.5 kW/m²).
- BAL-19: Moderate risk. Radiant heat up to 19 kW/m².
- BAL-29: High risk. Radiant heat up to 29 kW/m².
- BAL-40: Very high risk. Radiant heat up to 40 kW/m², plus a chance of flame contact.
- BAL-FZ (Flame Zone): Extreme risk. Direct flame contact and radiant heat above 40 kW/m².
Embers cause most bushfire home losses. They can travel kilometres ahead of a fire front and ignite gaps, vents and combustible materials, which is why even lower BAL levels require ember protection.
How do I find out my property’s BAL rating?
A BAL rating is determined by a site assessment. You can’t pick it or estimate it yourself. A qualified bushfire consultant or accredited assessor looks at:
- The type of vegetation around your site
- The distance from that vegetation to your building
- The slope of the land
- Your fire danger index (FDI), which varies by state
Your local council or building certifier can also confirm whether your block is in a designated bushfire-prone area. State rules can differ slightly, so always check local requirements.
What does a BAL rating mean for cladding?
Your BAL level decides which cladding materials you can use. Lower levels give you more freedom. Higher levels push you towards non-combustible products. Cladding isn’t just about the sheet. Fixings, flashings, sarking, and gap sealing must work together to block embers.
- BAL-LOW to BAL-12.5: Most standard cladding is acceptable, though ember protection still applies.
- BAL-19 to BAL-29: Non-combustible cladding such as fibre cement, brick, steel or masonry is the safest choice. Some bushfire-resistant timbers are also permitted, within limits.
- BAL-40: Choices narrow. Fibre cement, masonry and metal cladding are the go-to options, and joints, fixings and thickness matter.
- BAL-FZ: The strictest requirements apply, and non-combustible materials are essential. Some elements must also meet fire-test requirements.
What does a BAL rating mean for linings?
Linings, especially eaves, soffits, and gable linings, are common weak points because embers can lodge in them or enter the roof space. Higher BAL levels call for non-combustible lining sheets and tightly sealed joints.
BAL requirements don’t focus on internal linings such as plasterboard. Plasterboard does add some fire resistance, though, so it’s worth considering for walls that border garages or other higher-risk areas. Your certifier can confirm what’s needed for your plans.
Which cladding materials suit bushfire-prone areas?
Non-combustible materials are generally the best choice. The most common options for Australian builds are:
- Fibre cement: Strong, versatile, low maintenance and widely used across BAL levels.
- Steel and Colorbond cladding: Non-combustible, durable and a good fit for roofs and walls.
- Brick and masonry: Excellent heat resistance and long-lasting.
- Bushfire-resistant timber: Certain species, such as spotted gum, may be used up to BAL-29 in some applications, but they have limits.
What are the most common BAL mistakes builders make?
The most common mistake is assuming a material is compliant without checking it against the site’s specific BAL level. Others to avoid:
- Leaving small gaps or unsealed joints where embers can enter
- Using the wrong fixings or flashings for the cladding system
- Overlooking eaves, vents, and sub-floor areas
- Ordering materials before the BAL assessment is finalised
Getting the BAL assessment done early saves rework, delays, and cost.
Recommended products
Here are the product categories we suggest to meet BAL requirements across Australian builds:
- Fibre cement cladding sheets and planks: A strong all-rounder for external walls in BAL-12.5 to BAL-40 applications.
- Colorbond and steel wall cladding: Non-combustible, low maintenance and well suited to bushfire-prone regions.
- Non-combustible eaves and soffit lining sheets: Reduce ember entry at one of the most vulnerable parts of the house.
- Sarking and wall wrap: Choose bushfire-rated, flammability-tested products where required.
- Plasterboard (fire-rated): Useful for internal walls where extra fire resistance is needed.
- Sealants, flashings and fixings: The right accessories keep your cladding system compliant and ember-resistant.
Always confirm that each product is suitable for your property’s BAL rating before ordering.
Get your BAL-compliant materials delivered
Choosing the right materials is easier when your supplier knows the standards. At Building Supplies Australia Network, we stock one of the widest ranges of construction materials in the country. We deliver to major cities including Adelaide, Brisbane, Melbourne and Sydney, so your materials arrive when and where you need them. Order online today or request a quote, and our team will help you find the right products for your BAL level.