How Can we Build Houses that Better Withstand Bushfires?
This article was published in the Summer 2013-14 edition of Fire Australia magazine.
As we witnessed in September and October 2013 in NSW, transferring the suburban house into a setting susceptible to bushfires causes a lot of problems. Put simply: if you are going to live in a bushfire-prone area you should have a home that is designed and built differently. Our challenge is to create a new, better architectural form for bushfire-prone areas and to develop a way to upgrade existing homes.
Building to a standard
Regulators have sought to improve the bushfire protection of the standard Australian house by implementing measures from AS 3959 Construction of buildings in bushfire-prone areas.
This standard improves the fire performance of each building component, but as yet does not describe how these components could be assembled into a building. This design process is particularly complex; there is no one perfect solution, but rather a variety of options that can be selected for any individual building site.
Many organisations have been working in this area: CSIRO, AFAC, the Bushfire CRC, the Fire Protection Association Australia and several state and territory fire agencies and Australian tertiary institutions. I have been researching this area for my PhD and hope my findings can push the process ahead a little.
I asked residents in bushfire-prone areas which parts of their home they would take shelter in during a bushfire and which parts they would avoid. What was surprising was the large range of responses for both these questions.
While the bathroom was the most popular choice for taking shelter, with a focus on the ground floor to facilitate escape, there were up to 16 other places where residents planned to take shelter.
There were up to ten different places residents would avoid during a bushfire. They fell into four main categories: spaces with large amounts of glass facing the fire threat; lounge or living rooms; upstairs (because of limited escape); and the parts of the house closest to the direction of the expected bushfire threat.
Architects could use this knowledge when designing future homes in bushfire-prone areas. Bathrooms, for example, could be located at the junction of two outside walls and include an external door. Large expanses of glass facing the direction of the fire threat could be replaced with low walls with windows above.
The same residents were asked how their house could be improved to withstand a bushfire. They suggested bushfire shutters, roof sprinkler systems, non-combustible decking and verandas, mesh flyscreens, an underground area and increasing the cleared area around the house.
If incorporated, each of these would have to be validated, tested and improved by industry experts.
For example, a rooftop sprinkler system would require both a water supply and a generator to function. If the connections for either of these were inadequate the system would fail. Further research may produce ways to improve the reliability of these components.
There will need to be more work done on the materials we can use for future buildings. Researchers should also look at alternative options, such as having part of the house constructed underground or built into the side of a sloping block.
Not all is lost
Somewhere among the heartbreak of losing a home is the future opportunity to rebuild better than before.
This is a chance to both improve the fire protection of the house and make it energy efficient by trapping, storing and re-using energy and water. This is particularly relevant when the supply of grid power and mains water is interrupted, restricted or ceases altogether during a bushfire.
Thought should also be given to making the home a pleasant place to live, one that nurtures family life and individual reflection.
All of these things are achievable, but building such a house requires residents to change some of their perceptions about how their home will look and function.
Future homes are likely to be smaller, with fewer windows and no external timber. They will require regular maintenance, keeping energy efficiency devices in good condition and maintaining the carefully planted and cleared area around the house.
Making bushfire-responsive houses affordable to the majority of residents is a challenge that the architecture profession may wish to contribute to in several ways. Architects could elect to volunteer their services and help individual families to rebuild. However, this is a large and time-consuming task.
An architectural competition could be set up to find the most cost-effective designs that mitigate or remove the ways flying embers and direct flames contact from a bushfire gain entry into a house.
Having a resource of already prepared designs would be good. The painful dilemma of research in this field is that it takes time; people who have recently lost their homes have very real needs right now. For me it is personal, as many of the 252 residents who generously completed my questionnaire live in Springwood and other areas adversely affected in the Blue Mountains in October 2013.
I believe homes in bushfire-prone areas must achieve four integrated outcomes: increased bushfire protection, energy efficiency, affordability and, most of all, they should be a delight to live in.
It is possible to achieve all of these outcomes, but it will require looking at how they work independently and potentially together. This will become my post-doctoral research and be looked at from three perspectives: the design of future buildings in bushfire-prone areas; improving the fire performance of existing non-compliant AS 3959 buildings in bushfire-prone areas and rebuilding after a bushfire event.
Douglas Brown is writing his PhD and is aiming to finish in mid-2014.