The other aspect that struck me was there was no rebuilding taking place. No doubt the new building regulations have something to do with this. As well testing has been a problem finding a solution to roofing systems/procedures in the high bushfire attack levels (BALS) till (hopefully) recently. We will be able to get the latest information on the night of the seminar about this problem.
The Victorian Government announced the adoption of AS3959-2009 Construction of buildings in bushfire-prone areas in Victoria’s Building Regulations. In effect this means any new home built in Victoria must comply with AS3959. This fast tracking has led to misconceptions in the market place about the use of timber and timber products in bushfire prone areas. The seminar will discuss how timber products can be used across all the bushfire attack levels (BALS) including the most extreme category of BAL-FZ (Flame Zone). The mistaken promotion of using only
The other aspect that struck me was there was no rebuilding taking place. No doubt the new building regulations have something to do with this. As well testing has been a problem finding a solution to roofing systems/procedures in the high bushfire attack levels (BALS) till (hopefully) recently. We will be able to get the latest information on the night of the seminar about this problem.
The Victorian Government announced the adoption of AS3959-2009 Construction of buildings in bushfire-prone areas in Victoria's Building Regulations. In effect this means any new home built in Victoria must comply with AS3959. This fast tracking has led to misconceptions in the market place about the use of timber and timber products in bushfire prone areas. The seminar will discuss how timber products can be used across all the bushfire attack levels (BALS) including the most extreme category of BAL-FZ (Flame Zone).
The mistaken promotion of using only non timber products means the unnecessary adding of costs to the building. This is because timber sub-floor systems are better suited for sloping blocks. Rather than the more expensive and environmentally damaging cut and fill required for a concrete slab. Even on high BAL sites it is advisable to use a timber sub-floor. AS3959-2009 specifies when a timber sub-floor is fully enclosed, the traditional timber sub-floor framing products (stumps, bearers, joists) continue to be appropriate. For higher BALS, all vents in any enclosed sub-floor space need to be covered with a secure, appropriate metal mesh with maximum 2mm aperture to reduce risk of burning embers entering the sub-floor space.
External Cladding; there is still a wide range of options, including weatherboards and most lightweight cladding is still possible with careful choice of materials. For BAL-LOW, which most homes are, normal timber products and other lightweight cladding materials can be used. For BAL-12.5 and BAL-19, timber cladding needs to be bushfire resisting or made from timber species listed in AS3959E1 (species with density of 759/kg/m3 or greater) Joints in the cladding need to be sealed or the framing externally sarked.
If a home site is designated as BAL-40, it is worth considering building to the higher flame zone rating BAL-FZ, where a fire resistance level (FRL) of 30/30/30 is required. This can be achieved with a fire rated plaster/timber system which will actually give a higher rating (16mm fire rated plasterboard provides a 60/60/60FRL). Major plasterboard manufactures can supply more information on suitable products and simple, cost effective solutions.
Checking compliance certificates for high bushfire attack level materials; For high levels (BAL-40 & BAL-FZ) EXTERNAL BUILDING components need to prove they will perform in case of some attack. In some cases, this means ensuring the material or system you select has been certified as required by the standard. For BAL-40 certification to AS 1530.8.1 is required for; flooring materials (other than appropriately underlined timber flooring); and for materials (other than those defined as non-combustible), for fascias and bargeboards, unenclosed sub-floor spaces, decking materials and external cladding systems. For BAL-FZ AS 1530.8.2 is required for roofing systems, materials used in fascias, bargeboards and eaves linings, window systems, bushfire shutters, external doors and door systems and flooring systems when unenclosed, as well as decking. FRL performance is an alternative compliance requirement for some building material systems. In the case of lightweight cladding systems using a wet area, fire-grade plasterboard/timber system, manufacturers say they have found their systems actually have a higher rating, with 16mm plasterboard used, an FRL of 60/60/60.
It is important to ask for proof of performance certification before specifying or constructing in high bushfire-prone zones.
Source of some of the references; "Timber Housing in Bushfire-prone Areas" Bulletin No1 Issued by Wood. Naturally Better.
To revisit the presentations discussed on the night, please visit the following links listed below;
(1) Boris Iskra - Building in Timber in Bushfire-prone Areas. (Click here)
(2) Roger Crowley - Plasterboard lightweight solutions that satisfy AS3959-2009. (Click here)
(3) John Hay - Understanding procedures to obtain a BAL assessment. (Click here)
(4) Chris Francis - Window systems for bushfire-prone zones. (Click here)
For additional assistance or information, please feel free to email feedback@bowens.com.au or by calling Jeff Harvey directly on 0412 550 740.