Gutter Guard BAL-Ratings Explained 

“To buy BAL-rated gutter guards or not?” That question stumps many architects, builders, and tradespeople when planning construction in bushfire-risk areas. And you may be asking: so, what are BAL-rated gutter guards? BAL-rated gutter guards protect against ember penetration and flame exposure. They are assessed according to Bushfire Attack Level (BAL) ratings, ensuring they meet specific material, design, and durability standards to withstand bushfire conditions.

Your choice of gutter guard systems goes beyond mere functionality in areas threatened by bushfires. It’s about selecting a system that complies with BAL ratings and significantly bolsters a building’s defence against the unpredictable nature of bushfires. This article is dedicated to demystifying the impact of BAL ratings on gutter mesh selection for professionals in the construction industry. By exploring the intersection of BAL ratings and gutter guard specifications, we aim to equip architects, builders, and tradespeople with the knowledge to make informed decisions, ensuring their projects are compliant and resilient in the face of bushfire threats.

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Understanding BAL Ratings

Bushfire Attack Level ratings are a cornerstone of Australian building standards, designed to assess a property’s risk of bushfire exposure. These ratings range from BAL-LOW, indicating minimal risk, to BAL-FZ (Flame Zone), representing the highest risk. Each level dictates specific building materials and construction techniques, including gutter guard system installations, to enhance a structure’s resilience to bushfire threats.

There are different BAL ratings, each indicating a different level of bushfire risk:



Little to no risk.


Risk of embers, radiant heat up to 12.5KW/m² particularly those igniting surrounding vegetation.


Increased risk from embers and burning debris ignited by wind and potential exposure to radiant heat up to 19KW/m².


High risk, with increased ember attack and burning debris ignited by wind and even higher potential exposure to radiant heat up to 29KW/m².


Very high risk. Houses may be exposed to flames from the firefront, increased ember attack, and higher levels of radiant heat up 40KW/m².

BAL-FZ (Flame Zone)

Extremely high risk. Direct exposure to the flames from the fire front, ember attacks, and very high levels of radiant heat over 40KW/m².

The construction requirements for buildings increase with each level of BAL rating to enhance the structure’s resilience to bushfires. This may include specifications for things like the type of materials used, the design of the building, the type and placement of windows, and other features. Each state’s BAL ratings have consistent core principles across states and territories. All states and territories base their BAL ratings on the following:

  • Proximity to classified vegetation types.
  • The amount of vegetation (fuel).
  • The slope of the ground.
  • Fire danger indices.

It’s essential to note that determining the BAL rating for a property isn’t a simple matter. It considers various factors, including the type of vegetation surrounding the property, its distance from the property, and the slope of the land. If you are building or renovating in a bushfire-prone area, it’s crucial to have a professional assess the BAL rating of your property. This will ensure that you comply with local building regulations and best practices for safety.

bushfire protection

BAL Ratings State-by-State Overview

While the foundation of BAL ratings, based on the Australian Standard AS 3959-2018, is nationally consistent, local adaptations and regulations can vary, influencing how these standards are applied:

  • New South Wales (NSW): Here, additional state-specific guidelines complement the national standards, ensuring that buildings are equipped to withstand local bushfire conditions.
  • Victoria (VIC): The introduction of the Bushfire Management Overlay (BMO) adds another layer to the planning and construction process, tailoring bushfire defence measures to the region’s unique landscape.
  • Queensland (QLD) and Beyond: Each state, including South Australia, Western Australia, Tasmania, the Northern Territory, and the Australian Capital Territory, integrates the national standards with local insights, creating a nuanced regulatory environment that addresses the specific bushfire risks of each area.

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Australian Standard AS 3959-2018

The Australian Standard AS 3959-2018, “Construction of buildings in bushfire-prone areas,” provides guidelines on construction materials and methods suitable for various Bushfire Attack Levels (BALs). The standard categorizes bushfire risk into several BALs based on the potential exposure to ember attack, radiant heat, and direct flame contact. For each BAL, the standard provides requirements for various construction elements, from the site to floors, walls, windows, roofs, and more.

For the construction of roofs, including the use of a rated gutter guard and fire ember guard:

  • Materials: Ember guard mesh is to be made of non-combustible materials, which means they won’t ignite and spread flames. The term “non-combustible” is defined in the National Construction Code. Aluminium is generally suitable for BALs up to BAL-29. However, for BAL-40 and BAL-FZ, more robust materials, like steel or bronze, are recommended due to their higher resistance to heat and flames.
  • Aperture Size: The aperture size of a fire ember guard should be at most 2mm to effectively block out embers, which are a primary ignition source during bushfires.

Where to Find in the Document

The specifics regarding materials, construction methods, and other requirements are typically spread throughout the document, with sections dedicated to various construction elements.

  • The section on roofing (which would cover gutter and ember guard requirements) is an essential place to look.
  • Definitions and explanations of terms like “non-combustible” might be found towards the beginning of the document.
  • There may also be tables or appendices towards the end of the standard that summarize the requirements for each BAL.

To locate the exact details and specifications for ember and gutter guards, navigate to the standard section dedicated to roofing and external construction elements. However, for the precise location within AS 3959-2018, consulting the document’s table of contents or index would be the best approach.

For the utmost accuracy and to ensure compliance with the latest ember guard mesh regulations, it is always recommended to consult the standard directly or to work with a professional experienced in its application.

The Importance of Local Council Consultation

One of the most crucial steps in ensuring your project complies with BAL requirements is consulting with your local council. Local councils provide the most current and relevant BAL ratings and building requirements, which can vary significantly even within states. This step is not just about compliance; it’s about leveraging local expertise and resources to enhance the safety and resilience of your projects.

Role of Gutter Guards in Bushfire Defence

Gutter guard systems are not just about preventing clogged gutters; they’re a critical component in a property’s defence strategy against bushfires and wind-borne embers. By blocking airborne embers and preventing them from igniting debris within gutters, ember guards play a crucial role in enhancing a building’s resilience. However, it’s essential to choose the right ember guard materials. In gutter protection, ember guard products are the compliant gutter guard solution for any bushfire-prone area for gutter protection.

What is Ember Mesh?

Ember mesh refers to a specialised type of mesh designed to protect buildings and structures from the intrusion of embers during a bushfire. This mesh is typically installed over openings such as vents, eaves, and especially gutters and downpipes to prevent embers from entering and igniting materials inside or accumulating in areas that could lead to a fire.
Ember mesh is made from non-combustible materials, such as certain metals, to withstand high temperatures without igniting.

aluminium ember mesh ember guard

Ember mesh is characterised by its fine weave, with apertures small enough (usually not more than 2mm) to block embers’ passage while allowing for ventilation and water flow, unlike typical gutter mesh. The use of ember guard is a critical component in building design and construction in bushfire-prone areas, helping to enhance the structure’s resilience against the threat of ember attack, one of the primary ways bushfires spread to residential areas.

While aluminium guards are suitable up to BAL-29, higher-risk areas (BAL-40 and BAL-FZ) require more robust materials like steel or bronze, known for their superior resistance to heat and flames.

steel mesh

Ember & Gutter Guard Mesh State Specifications

Ember and gutter guard specifics can vary by state and territory, reflecting each jurisdiction’s unique fire behaviours, climates, and local experiences.

Let’s break down the key requirements or differences for ember guards in each state and territory based on the Australian Standard AS 3959-2018 and local variations:


New South Wales (NSW)

  • Ember guards are required for buildings in bushfire-prone areas with a BAL rating of 12.5 or higher.
  • Ember mesh is non-combustible and has a maximum aperture of 2mm.
  • Aluminium is appropriate for BAL levels up to BAL29, but steel or bronze are used for higher BAL levels, like BAL-40 and BAL-FZ.

Victoria (VIC)

  • For areas with BAL-12.5 and above, non-combustible ember guards with an aperture of 2mm or less are required.
  • Victoria emphasises a holistic approach, incorporating the Bushfire Management Overlay into planning.
  • Aluminium is appropriate for BAL levels up to BAL29, but steel or bronze are used for higher BAL levels, like BAL-40 and BAL-FZ.

Queensland (QLD)

  • Queensland mandates ember guards for homes with a BAL rating of 12.5 or higher.
  • They must be non-combustible with a maximum aperture of 2mm.
  • Material specifics vary based on location and local council regulations, but the state typically follows the guidelines in AS 3959-2018.

South Australia (SA)

  • Homes in areas with BAL-12.5 and above must have ember guards.
  • They should be constructed of non-combustible material with a maximum aperture of 2mm.
  • Aluminium is appropriate for BAL levels up to BAL29, but steel or bronze are used for higher BAL levels, like BAL-40 and BAL-FZ.

Western Australia (WA)

  • Western Australia requires ember guards for homes in BAL-12.5 or higher areas.
  • As with other states, the gutter mesh must be non-combustible and have an aperture of 2mm or less.
  • WA has additional guidelines that supplement AS 3959-2018, and while they follow the general principles, there might be local variations or interpretations. It's advisable to consult local guidelines to be sure.

Tasmania (TAS)

  • Ember guard is necessary for homes in areas with BAL-12.5 or higher.
  • They should be non-combustible and have a maximum gap size of 2mm.
  • Aluminium is appropriate for BAL levels up to BAL29, but bronze or steel mesh are used for higher BAL levels, like BAL-40 and BAL-FZ.

Northern Territory (NT)

  • The NT may have less emphasis on bushfire standards due to its different climate and vegetation. However, where relevant, an ember guard with non-combustible materials and a maximum aperture of 2mm would align with the national standard.

Australian Capital Territory (ACT)

  • The ACT requires an ember guard for homes with a BAL rating of 12.5 or higher.
  • These gutter guards should be non-combustible with an aperture size not exceeding 2mm.
  • Aluminium is appropriate for BAL levels up to BAL29, but steel or bronze are used for higher BAL levels, like BAL-40 and BAL-FZ.

While the general requirement for an ember guard — being non-combustible and having a maximum aperture of 2mm — is relatively consistent across all states and territories, the application, enforcement, and additional considerations can vary. It’s also important to remember that local councils may have specific gutter protection requirements or recommendations based on localised risks. Always refer to local regulations and guidelines when planning or retrofitting ember guard and gutter mesh.

Other Differences Across States

While the core BAL ratings remain the same, states and territories may:

  • Have Additional Local Regulations: Some jurisdictions might introduce supplementary requirements for construction, planning, and vegetation management based on local fire history, climate, and other factors.
  • Use Different Mapping Tools: While some states may use a broad-brush mapping approach to identify bushfire-prone areas, others might use a finer-grained approach.
  • Differ in Application Processes: The process to get a BAL assessment, planning permissions, or exemptions can vary between states.
  • Local Fire Danger Indices: Part of the BAL calculation, Fire danger indices can differ by state and region. This reflects local weather, vegetation, and fire behaviour patterns.

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Screen Tech's BAL-Rated Products

Understanding and adhering to Bushfire Attack Level ratings is more than a regulatory requirement; it’s a commitment to safety and resilience in the face of Australia’s bushfire challenges. As a supplier dedicated to providing top-tier gutter guard solutions, we encourage all architects and tradespeople to stay informed about state-specific requirements and always consult with local councils in their planning and construction process.

Are you ready to ensure your next project is bushfire-resilient with the right gutter guard solutions? Contact us today to discuss your needs, explore our range of products, and find out how we can help you meet and exceed Bushfire Attack Level requirements across Australia.

ScreenTech is an industry leader in bushfire-rated ember guard and gutter guard solutions and wholesale supply for tradespeople, architects and construction firms. Speak with one of our team members today to learn more about our aluminium TuffMesh® and GutterMesh ranges and our SteelMesh range.

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