BAL! What’s it mean.
BAL, three letters that can make a big difference to your new house plans. Bushfire Attack Level (BAL), if you would like to review in detail the Australian Standard is AS3959 with the relevant revision or please make an appointment to discuss with us in office or via video conference.
Firstly lets start with the basics: BAL Low, 12.5, 19, 29, 40 and FZ (Flame Zone). To find out if you need an assessment, you can review your address on the Bushfire Prone Map on the DFES website (https://maps.slip.wa.gov.au/landgate/bushfireprone/),. Basically, if you are in the pink, you need to give a BAL assessor a call. If you haven’t purchased the site yet and have no house plans, you can opt in for a predevelopment/pre-build plan assessment with a Bushfire consultant. If your site is BAL Low - you're in luck! With BAL Low, there’s no real changes for you to consider in an Australian Standard way. The bushfire levels higher than BAL Low do require extra thought and consideration - it's worth going in and seeing an architect as it will determine certain design aspects that may be a deal breaker for you.
When we break it down further, BAL 12.5 and 19 are on the lower end of the spectrum and can be tackled with some clever design. Your selections of materials are reduced (but not significantly), and you have options. Check out these two product websites for some inspo ides: https://www.jameshardie.com.au/ and https://colorbond.com/gallery. Just remember if you have a taste for timber when you go see your architect check what timber options are available for your BAL rating. The higher the BAL's (29, 40 and FZ), the range of selection is reduced further as any material that is potentially flammable is removed as an option due to the chance that the flames will be getting closer to your home. It can also use up more and more of your money as it is normally an extra expense on a standard home.
Glazing is another major design item that can be effected by the level of BAL you receive. If you are planning on having large glazing and your BAL is on the higher side, then it can require that you have certain thickness of glass, protective screens or even a bush fire rated shutter. There are design techniques to reduce down the requirements such as lifting the sill height above 400mm, having raised floor levels and creating screens that become part of the design.
I always like to think nothing is impossible with design. Being an architect is all about problem solving. The only thing we can’t do (unfortunately) is make your budget grow. If you have a restricted budget consider the effect of that when you select a property that has BAL restrictions, as higher BAL levels can translate directly to higher costs. Selecting a less restrictive property or reducing down the overall size of the house to compensate for any additional cost that result from a BAL level above Low will need to be seriously considered.
Further important points to raise are:
Insurance for your home once it is complete. Will your insurance company cover your home with high BAL rating?
Continuing the maintenance on the surrounding vegetation on your property. Normally a 20m protection zone, however can differ with different recommendations.
Having a Bush Fire Plan in place if you do need to leave your home in an emergency.
The Australian standards AS3959 is not designed to allow for you to stay at your home in the case of an emergency. Instead, the required use of certain materials and finishes are to allow for you and your family to exit from the home to safety.
Restrictions (as always) do create an opportunity for interesting designs, and hopefully your architect sees these conditions as a design challenge rather than a barrier. If you have any questions please send them through.
Thanks for reading,