bushfire protection cladding exterior

Bushfire protection

Building in bushfire prone areas comes with additional considerations. HOUSING talks to a HIA member who has achieved Passive House certification to BAL-FZ, plus looks at several products that will help you to meet BAL standards on your next project.

For more than 15 years managing director Joe Mercieca and his wife Merylese of Blue Eco Homes have been building sustainable custom-built homes in the Blue Mountains, an area west of Sydney well-known for its World Heritage bushland. Proximity to vast tracts of ancient eucalypt forests has not only meant adhering to bushfire attack level regulations (BAL), but has driven their pursuit of better sustainable practices in the ecologically-sensitive housing they produce for the region.

‘We’re always trying to improve the way our buildings are built so they can be more sustainable and efficient,’ Joe says. ‘We’re also trying to iron out the issues that people experience in homes, like high energy costs, mould growth and comfort levels.’

After extensive research, HIA members Joe and Merylese were soon persuaded that Passive House (or Passivhaus) would address many of these building issues and improve the design of Australian homes. This rigorous construction standard, which originated in Germany, is design-led and based on building physics to deliver high-performing homes for their entire lifetime.

So, looking for their next challenge, Joe and Merylese decided to try it for themselves, and following ‘a good number of years’ of planning, designing and building, they unveiled The Sapphire – their first certified Passive House display home.

The single-level four-bedroom property is carbon-zero and features a striking exterior in contrasting shades of charcoal and grey, along with a raked roofline for a spacious interior. Abundant natural light filters through strategically placed windows, balanced by a white and timber kitchen, and lightly-hued polished concrete flooring. 

Blue Eco Homes The Sapphire Passive House BAL-FZ exterior
The Sapphire is one of the first known certified Passive Houses to BAL-FZ in Australia, and possibly the world.
Photo courtesy Blue Eco Homes
Blue Eco Homes The Sapphire Passive House BAL-FZ interior
The Sapphire's raked roofline provides a spacious interior, while its timber kitchen is balanced by the lightly-hued polished concrete floor. 
Photo courtesy Blue Eco Homes

While producing a stylish dwelling and passing the stringent levels for certification made this one of Joe’s more challenging builds to date – another aspect that ‘posed a few issues’ was building to BAL-FZ, since the five-acre subdivision site backed onto a steep gully and was deemed to be a flame zone (the highest BAL regulation).  

Some of the materials used to ensure the home was adequately equipped with the right bushfire defences included: a Colorbond corrugated roof in Custom Orb; UPVC aluminum-clad triple-glazed windows and doors (imported from Germany); structural steel (as required for bracing); external cladding in fire-rated Inex Board; plywood and external shutters to BAL-FZ. 

Besides these considerations, Joe says that when building a Passive House ‘there are no assumptions, everything is quantified and calculated on the whole lot’. 

‘[Sapphire] is a very technical house,’ he says. ‘We worked with our certifier to complete the modelling and just kept at it until we got it right.’

One of the principles of Passive House is eliminating thermal bridges. This refers to points in the building that allow heat or cold to con-duct more quickly than the rest of the structure, compromising the overall performance of the insulation. 

‘We had to calculate the thermal conductivity of each screw in the wall so that we would get our insulation correct,’ Joe explains. ‘When you have 3000 screws just on the external cladding, it all adds up! That’s how far the thermal modelling for this house goes.’

Other calculations included air tightness. The required level was a minimum of 0.6 air changes an hour, but the house is performing at 0.39 air changes per hour. 

‘The house breathes, but it doesn’t let moisture transfer in and out. It’s important that your wall and roof systems breathe so condensation doesn’t build up.’

Asked if the endeavour was a success, Joe says ‘100 per cent’: ‘High-performance glazing, insulation and an airtight building ensures the internal temperature is constantly kept at a comfortable level ranging from 20–25˚C, with minimal reliance on artificial heating or cooling. We estimate running the entire house is only about 13.3kW per day without solar, so we’ll be putting more into the grid than we’ll be using.’

Joe says it was an ‘intense’ process at times, but not only was the project a first for Blue Eco Homes, The Sapphire is one of the first known certified Passive Houses to BAL-FZ in Australia, and possibly the world, according to the Passive House Association. 

‘We’re all very proud about what we achieved. The house looks good and is working tremendously. We built it to teach and show people it can be done, so we’re looking forward to the next one and making it easier for people to obtain.’

Blue Eco Homes The Sapphire Passive House BAL-FZ

Design details

Builder: Blue Eco Homes
Location: Blue Mountains, NSW

Materials:

  • Roofing: Colorbond in Custom Orb
  • Windows: Triple-glazed UPVC windows and external doors, Neufer 
  • Cladding (to FZ): Inex Board
  • Internal/external wraps: Pro Clima
  • Heat Recovery Ventilation System: Plus Energy Living
  • Shutters (to FZ): Block Out Shutters
  • Solar: 5kW LG solar PV system, SMA inverter, Tigo Optimisers, 10kW LG battery storage: Solar Juice
  • Concrete slab/floors: Hanson
  • Tiles: Beaumont Stone Depot

Stylish and sturdy cladding

Choosing your building materials is an all-important consideration when building or renovating a house in bushfire prone areas and it will invariably impact on its design. But the quest for compliance with designated bushfire attack levels and functionality doesn’t mean you need to compromise on style.

Homeowners and builders alike can enjoy maximum impact and minimum hassle with DecoClad, DECO’s fire-safe cladding profiles. Made from 100 per cent solid aluminium, the range offers a timber-like appearance in five contemporary styles, including Shadowline, Narrowline and Weatherboard.

The lightweight DecoClad profiles can be used vertically or horizontally and are suitable for a range of residential and commercial applications, including external walls and facades, ceilings, gable ends and soffits. All DecoClad designs are also available in DecoWood’s Super Durable™ powder-coated natural woodgrain finishes or standard powder coat colours. 

DecoClad is a non-combustible product meeting the NCC testing standard AS1530.1 and is also tested to AS1530.3. It can be used in bush-fire prone areas up to BAL 40, as well as up to BAL-FZ when using a fire-barrier product.

The product also features a patented interlocking system and pre-punched fixing for fast and easy installation. The system includes a range of accessories to achieve a seamless, concealed fixing. 

bushfire protection exterior
DecoClad is DECO’s fire-safe cladding made from 100 per cent solid aluminium. The range offers a timber-like appearance in five contemporary styles.
Image: supplied
bushfire protection cladding exterior
DecoClad profiles can be used vertically or horizontally and are suitable for a range of residential and commercial applications.
Image: supplied

Lightweight polymer formwork

Building in bushfire prone areas can come with a raft of issues, from a difficult to access site, a house design that includes a basement wall located below the water table or a location that requires building products rated for use in BAL-FZ areas, which are prone to the worst bush-fire conditions. 

Dincel structural walling is a permanent polymer formwork system that can address these issues with one solution. Dincel says it has been assessed to meet the NCC bushfire regulations for BAL-FZ areas in accordance with AS 3959. It has also been tested to other fire regulations by a NATA-registered laboratory, including ISO 9705–Deemed to satisfy (Group 1, SMOGRA 14); AS 5113/BA 8414 (Performance Solution); and AS 1530.4–FRL between 90/90/90 and 240/240/240.

Dincel is lightweight, and with an international patent for its snap lock technology, allows for easy manoeuvrability and assembly onsite. With relatively simple installation provisions and no need for cranage, builders can save on construction time and labour.

In a site that is hard to access where basement walls are involved, Dincel’s ability to work as a waterproof permanent formwork skin, even when below the water table, may reduce the amount of excavation required for the build. This skin means you don’t need the extra room for access to install waterproofing membranes on the wall surface when compared to blockwork or standard formwork methods, translating to more cost-savings in labour and waterproofing membrane materials. 

Dincel says its panels and panel joints have been tested and assessed by CSIRO as waterproof under a six-metre head pressure, and therefore can be used for swimming pools or water tanks in a bushfire area. 

Dincel bushfire protection
Dincel is lightweight, and with an international patent for its snap lock technology, allows for easy manoeuvrability and assembly onsite. 
Image: supplied
Dincel bushfire protection
In a site that is hard to access where basement walls are involved, Dincel’s ability to work as a waterproof permanent formwork skin, even when below the water table, may reduce the amount of excavation required for the build.  
Image: supplied

Ignition barrier coating

To protect homes in bushfire prone areas, you’ll want a product that can stop the ignition of embers and flames spreading. Australian company EXFIRE offers FIRESHELL F1E ignition barrier coating, which has been designed and tested specially for these types of external environments. The product stems from a high-grade exterior primer background and provides good exterior fire protection performance. 

FIRESHELL F1E’s performance on pine is a sustainable alternative to using hardwood for a range of building applications in bushfire zones. In particular, it is a good choice for exposed decking subfloor areas and joists bearers, while posts can be coated pre- or post-construction with compliant decking laid on top. Pine and cedar cladding can also be used in BAL12.5, BAL19 and BAL29 applications.

The low-VOC water-based system also offers a range of risk reduction and asset protection solutions by creating an ignition barrier on external combustible surfaces. 
FIRESHELL F1E has undergone extensive testing to demonstrate compliance with both the accelerated weathering and fire test requirements of AS3959 for bushfire-resisting timber applications. It also demonstrates suitability for use to reclassify pine, cedar and other species as bushfire-resisting timber, up to and including, BAL29 applications. The barrier coating has also been tested for compliance to ISSO 5660 applications.

EXFIRE says it has an experienced technical support team who have a wealth of knowledge and understanding regarding AS3959 requirements. All NATA test certificates and reports are available upon request, with detailed support available throughout the process to assist with your build.

This article was compiled with contributions from DECO, Dincel and EXFIRE

EXFIRE bushfire protection ignition barrier coating
FIRESHELL F1E’s performance on pine is a sustainable alternative to using hardwood for a range of building applications in bushfire zones.
Image: supplied

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