Bush Fire Resistant Granny Flats.

In November 2015, Baldwin O'Bryan Architects won the Bushfire Building Council of Australia's  Innovation Award for the best design concept for this design at Newee Creek in NSW.

MODULAR EARTH SHELTERED GRANNY FLATS

Prefabricated modular steel frame construction is a highly cost-effective alternative to reinforced concrete. This type of construction can be made equally bushfire-resistant and offers the same exceptional thermal benefits as reinforced-concrete, earth-sheltered houses. The graphics above show three alternatives for a 60-square-metre granny flat. The first alternative features a fully vegetated roof with at least 300 mm of soil cover. The second, which costs less than the first, has a heavily insulated metal deck roof that can meet FZ BAL construction standards under AS 3959. The third uses a metal deck roof without side retaining walls, significantly reducing costs compared with the first two options.  This technology can also be applied to much larger houses and to commercial and industrial buildings 

PREFABRICATED EARTH SHELTERED GRANNY FLATS WITH A STEEL FRAME AND 4 HR FIRE RATED EPS CONCRETE PANELS

CLICK ON ALL IMAGES TO ENLARGE   
​WE HAVE DEVELOPED AN INNOVATIVE, COST-EFFECTIVE CONSTRUCTION APPROACH BASED ON EPS CONCRETE PANELS COMBINED WITH A STEEL FRAME SYSTEM.
This method enables us to achieve high bushfire performance without the prohibitive costs often associated with traditional reinforced concrete construction. One of the main challenges in bushfire-resilient design is balancing performance with affordability. While heavy reinforced concrete structures provide excellent fire resistance, they are often costly and slow to erect, making them inaccessible for many homeowners. EPS concrete panel systems, on the other hand, can deliver comparable fire performance at a fraction of the cost and allow for quicker construction. To illustrate, one of our clients received quotes from over six different builders, all of whom estimated building their house above $2.4 million using reinforced concrete. In contrast, the same project was priced at $850,000 when using EPS panels.

EPS concrete panel and steel frame system offers several key advantages:
  • Bushfire performance: Engineered EPS concrete panels can deliver up to a four-hour fire resistance rating, enabling compliance up to BAL-FZ conditions.
  • Cost efficiency: Compared to solid reinforced concrete, this system significantly reduces construction costs while maintaining comparable fire resistance.
  • Thermal performance: The insulating properties of expanded polystyrene combined with concrete provide superior thermal performance compared to dense reinforced concrete, reducing ongoing heating and cooling loads.
  • Acoustic benefits: The composite panel system offers enhanced sound insulation, which is particularly beneficial in coastal and bushland environments.
  • Design flexibility: Panels can be rendered or finished to replicate off-form concrete with minimal additional cost, allowing architectural flexibility without compromising performance.
Having the right professional team is critical. A refusal from authorities such as the CFA in Victoria, the RFS in NSW, or local councils can be extremely difficult to overturn once issued. Early, informed design decisions are essential to avoiding costly delays or refusals. a bushfire-resistant granny flat in a bushfire-prone area offers significant benefits, including enhanced safety, property protection, and potential financial advantages. These advantages stem from adhering to construction standards that improve a building's ability to withstand ember attack, radiant heat, and flame contact.
Key Advantages
  • Increased Safety for Occupants: The primary objective of bushfire-resistant construction is to provide a measure of protection for occupants until the fire front passes, allowing fit and well-prepared people to shelter or safely evacuate.
  • Minimised Property Damage: Utilizing materials like non-combustible cladding, steel roofing, and toughened glass significantly reduces the risk of the structure igniting from embers, which account for a high percentage of house losses.
  • Reduced Financial Loss and Insurability: A more resilient home lessens the potential for extensive damage and financial loss during a bushfire event. It may also help streamline insurance coverage discussions, as some standard policies may not automatically cover a new dwelling in a high-risk area.
  • Improved Energy Efficiency: Many bushfire-resilient upgrades, such as better sealing, sarking, and insulation, also enhance the building's thermal performance, leading to reduced energy costs for heating and cooling.
  • Streamlined Approvals Process: In New South Wales (NSW), properties meeting specific Bushfire Attack Levels (BAL-LOW to BAL-29) can qualify for faster Complying Development (CDC) approvals, avoiding lengthy council Development Application (DA) processes.
  • Enhanced Peace of Mind: Investing in a resilient structure provides homeowners with confidence and peace of mind that their property and loved ones have a higher level of protection against increasingly common and severe extreme weather events.
  • Increased Property Value and Versatility: A well-built, bushfire-compliant granny flat can increase overall property value and offer versatile space for family, guests, a home office, or a potential rental income stream.


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How to Check if Your Granny Flat, Shed, or Studio is in Bushfire-Prone Land
You can check if your granny flat, shed, or studio is in bushfire-prone land by visiting the websites below, according to the state that you are in.
New South Wales (NSW)
Victoria (VIC)
Queensland (QLD)
South Australia (SA)
Western Australia (WA)
Building to the relevant Australian Standard (AS 3959) is mandatory under the National Construction Code in designated bushfire-prone areas. While no building is entirely "bushfire-proof" in extreme conditions, compliance significantly improves its resilience and survivability.
Explore the benefits of bushfire-resistant granny flats, including enhanced safety and reduced property damage in prone areas: