The vast majority of homes destroyed during bushfires are victims of ember attack, meaning they ignite and burn due to contact with windborne embers (burning debris) rather than direct flame contact.
Your gutters are a prime source of such ember attacks. They make you vulnerable to ember attack in two significant ways – by providing easy fuel for embers, and by offering embers easy entry to roof cavity.
Vulnerability to embers
1. Inside your gutters
Dry leaves in gutters are a source of fuel that can be ignited by bushfire embers. Unprotected gutters and poorly specified gutter mesh are the main reason for this problem; however, poorly-specified gutter mesh can also leave you vulnerable to this threat by allowing leaves to enter your gutters.
2. Inside your building
Embers can get inside your building through small gaps between your roof, gutters and fascia. They can then start a fire when they land on insulation or other fuel sources. Only a gutter mesh made from materials approved to the Australian standard AS3959-2009 such as corrosion-resistant steel, and with an aperture of 2mm or smaller, will keep embers out of your gutters.
Understanding bushfire compliance
AS3959–2009
Australian Standard AS3959-2009 Construction of buildings in bushfire prone areas, mandates different construction requirements based on your property’s BAL (Bushfire Attack Level).
Designed to improve the ability of new homes to withstand bushfire and ember attack, the standard affects your choice of construction materials for a number of features around your home, including gutter guards such as gutter mesh.
Ember guard compliance
Ember guards stop burning embers getting into your home through gaps greater than 3mm. They can be made from a non-combustible mesh with an aperture (hole size) of 2mm or smaller. Mandatory for all new homes built in a bushfire-prone area with a BAL of 12.5 or higher, they’re used to “seal” any gaps greater than 3mm, such as gaps around your roof sheeting.
For homes in areas with a BAL of 12.5, 19 or 29, ember guards can be manufactured from corrosion-resistant steel, bronze or aluminium. For homes in areas with a BAL of 40 or higher, only corrosion-resistant steel or bronze ember guards are allowed. Corrosion-resistant steel gutter mesh with an aperture of 2mm is an ideal ember guard solution.
Gutter guard compliance
According to AS3959–2009, gutter guards are optional for anyone building a new home in an area with a BAL of 12.5, 19, 29, 40 or FZ. However, if you choose to use them, the standard states: “if installed, gutter guards shall be non-combustible”. All Blue Mountain Co Gutter Mesh is non-combustible and complies to the Australian standards.
Most gutter guards are NOT ember guards, but Blue Mountain Co 2mm steel mesh is both an ember guard and gutter guard. It is compliant with both requirements.
