Achieving housing affordability with timber
One of the problems with introducing medium density housing in the outer suburbs is doing so in a cost-effective way, without compromising on quality. New prefab technologies like those presented at the Frame Australia conference offer some very compelling solutions.
Building with timber frame and engineered wood construction is becoming a preferred option to meet the challenge of providing affordable medium density housing, according to some property developers.
The key driver for this ‘new thinking’ in residential construction is the trend in planning by many state governments to increase the density of housing in the inner and middle suburbs to keep the increasing sprawl of our major city boundaries in check.
For developers, this increased density requires multiple levels to cover high land costs, resulting in medium-rise housing being economically viable at four to five storeys to give adequate financial returns.
Buildings of this height and beyond have been built in other countries for many years using timber framing. They’re now being assisted here by recent changes to the Building Code which allow three storey timber buildings – with suggestions that the next step could be allowances in the Code for more levels.
At present, the construction of a timber frame building over three storeys requires extensive engineering documentation, but the cost is more than recouped by savings in construction on a typically cramped inner-suburb building site – particularly when compared to the traditional materials of steel and concrete.
This topic was discussed at the recent Frame Australia conference in Melbourne, where it was revealed that there are many timber building solutions currently available to lower the square-metre cost of construction for multiple housing developments.
In a presentation by Kase Jong, Estimating Manager for major developer Australand Property Group, he explained “Our objective is to not only meet customer expectations but to have attractive and cost efficient buildings.
“To obtain cost savings we have changed the way our buildings are designed, to enable domestic construction labour and materials to be used which results in savings up to 25% per apartment.
“We are using hybrid construction to build 5 storey timber-framed structures utilising prefabricated frames with panelised floor cassettes, creating a system that is built off-site and installed in modules.
“The method provides significant benefits in saving construction time and improving safety, and utilises readily available building materials normally used in the supply chain for detached housing.”
Kase continued “for Australand, this building method can be applied to about 50% of our medium-density houses and apartments. It’s about finding the right solution to the right site for each situation.
“This enables us to provide more affordable housing for the average Australian in the middle and outer suburbs where concrete construction is not economically viable.”
Kase also presented details of Australand’s Parkville project ‘The Green’ (pictured left) which contains 57 apartments across five storeys, with a building area of 5,100 square metres. Using timber frame construction the development took only 12 months from start on site to Certificate of Occupancy issued.
In another presentation , international expert Walter Fahrenschon, CEO of Hundegger Germany said “Prefabrication is an ideal solution to build better quality houses at competitive pricing, through greater accuracy providing better finishes and improved building performance in energy efficiency and acoustics.
“Does higher quality cost more? The answer is yes if we try to raise quality with the same building methods, but the answer is no if we are willing and able to change the processes and methods of construction,” he added.
Walter’s suggestion from his experience in quality improvements in Europe was to “start with multiple housing developments, as the construction time reduction is very important, and high quality in building acoustics and finishes are also important to the buyer.”
The Frame Australia exhibition featured a large number of timber building products including Tecbeam, a high performance beam component of floor cassettes in the Australand Parkville development.
Jack Haber, Executive Chairman of Tecbuild Systems, which manufactures Tecbeam explained that “cost savings from speed in construction and reduced materials costs is being enhanced by superior performance from new-generation products and building systems.
“These provide longer spans, stiffer floor plates and superior fire and acoustic results for a better overall result.
“Importantly, these systems are available through well-established existing and competitive supply chains. And right now timber panelised solutions are being brought to the Australian market that will allow developers and builders the opportunity to pass savings advantages on to purchasers.”
Jack cautioned that “prefabricated solutions are fully engineered, and must be carefully detailed. The key to a successful project is to carefully select a capable fabricator and to include them as part of the design team from the start.
“Successful prefabrication is the result of care and expertise brought to the shop drawings, which include such key considerations as engineering and certification, lifting design, wall set-out drawings, and services coordination” he concluded.
The general consensus at Frame Australia was that ongoing containment of urban sprawl will be necessary for healthy cities, and prefabricated timber frame medium density housing construction of five storeys and more will be the solution.
There is no doubt that future infill housing in areas closer to cities must be delivered to the market at affordable prices to ensure the population density targets are achieved – which effectively places the responsibility for this outcome in the hands of the building industry.