Updated 26 October 2026.
A Bushfire Attack Level (BAL) describes a building site’s potential exposure to embers, radiant heat and flames. It helps determine the construction requirements for a property in a bushfire-prone area.
For gutter protection, the practical questions are which materials suit the assessed site, how the system will be fitted, and how it will be maintained. This guide brings together the BAL levels and a checklist for discussing gutter guards with your builder or installer.
BAL ratings explained
A BAL assessment considers the surrounding vegetation, its distance from the proposed building, the slope of the land and other site conditions. AS 3959:2018, Construction of buildings in bushfire-prone areas, is an important reference for assessing exposure and selecting construction measures.
The six levels describe increasing bushfire exposure. A gutter guard’s material or product name does not establish the BAL of a property.
- BAL–LOW: exposure is too low to require specific bushfire construction measures under the BAL classification. Ember attack can still occur.
- BAL–12.5: primarily exposure to embers, with relatively low radiant heat.
- BAL–19: increasing ember and burning-debris exposure, together with radiant heat.
- BAL–29: high exposure to embers, burning debris and radiant heat.
- BAL–40: very high exposure, with some possibility of direct flames.
- BAL–FZ (Flame Zone): extreme exposure, including likely direct flame contact as well as radiant heat and embers.
What to do after a BAL assessment
Start with your property’s assessment and approved plans. Ask your building surveyor, designer or bushfire consultant which requirements apply to the roof, gutters, valleys and other openings. Local planning and building requirements can also affect the project.
- Confirm the assessed BAL and the requirements for your particular building.
- Ask for documentation for the exact mesh, coating, fixings and installation method being proposed.
- Check roof details such as box gutters, valleys, roof penetrations and access for maintenance.
- Keep the product information and installation records with your building documents.
For an existing home, discuss suitable upgrades with a qualified practitioner. Vegetation work and other site changes should follow applicable local requirements.
How BAL affects your choice of gutter guard
Leaves and twigs in gutters can become fuel for windborne embers. An appropriate gutter protection system can help reduce debris accumulation as part of a wider roof and property maintenance plan.
The Australian Government’s YourHome bushfire protection guide recommends considering non-combustible gutter guards. The choice for your property should follow its assessment, approved design and the documentation for the proposed system.
Gutter guards, ember mesh and maintenance
A leaf guard primarily helps keep larger debris out of a gutter. Mesh used to protect an opening from ember entry has a different role. Do not assume that every metal mesh or every leaf guard is suitable for every opening or BAL level.
Ask the project team to confirm the required aperture, material, fixing method and treatment of gaps for each location. Particular attention may be needed at roof edges, junctions and penetrations.
Gutter guards do not make a home fireproof or remove the need for inspection. Check for debris on top of the mesh, in valleys and around roof equipment, and arrange safe cleaning and maintenance as needed.
Discuss a documented gutter guard solution with AGP
AGP can discuss roof type, gutter layout, access and mesh options for your project. Share your BAL assessment and any relevant plans when requesting a quote. Ask for the documentation for the exact product and installation proposed for your property.
Explore our bushfire protection gutter guard service, mesh materials and certification and compliance information.
Further reading
Aussie Gutter Protection offers a wide range of products, materials and hole sizes. Our ranges include:
