TIMBER
utilised in a panelised fashion. While perhaps lacking the natural beauty of the massive options identified earlier, this system is highly efficient and structurally sound in buildings of up to eight storeys. With capacity within the industry to fabricate wall frames and floor cassettes in a highly efficient frame and truss plant, the lightweight solution is an attractive option for most mid-rise Class 2 and 3 buildings.
COSTING TIMBER So how is costing timber different to costing any other building material? In reality, it’s not the timber that changes things, it’s what the timber allows the design team and builder to do. Engineered timber products are fabricated to order, facilitating further prefabrication if required, they are light (timber is 20% the weight of reinforced concrete), they are easy to fix to (think an impact driver and some screws rather than a hammer drill and epoxy), their assembly requires no wet trades or hot works. They can be lifted with edge protection pre-installed, essentially avoiding live edges altogether. What’s more, timber floor panels (whether massive or cassette) require no propping, meaning services rough in can commence the day after a floor above is installed. When combined, these factors have been seen to result in on site programs that are almost a third shorter than if the building were built following traditional in-situ techniques. This saving is well illustrated in the case of Forte, Australia’s first mid-rise timber project. Constructed by Lendlease in Melbourne’s Docklands in 2012, this 9-storey project was installed on site by a team of up to 6 people (including crane crew) in just 10 weeks. This time saving directly impacts all time related costs in the project, including preliminary costs for the builder, interest costs for the developer, and risk exposure
for all parties involved. While time savings generally account for the largest proportion of cost savings in a timber project, other characteristics unique to timber can result in further savings. For example, the light weight of timber means that massive timber panels rarely exceed 2 tonnes, and lightweight panels rarely exceed 1.5 tonnes. This comparatively small weight allows for the use of lower capacity cranes on a project, reducing both the weekly hire and footing costs.
International House Sydney image acknowledgements: Designed by Tzannes architects for Lendlease. Photography by Ben Guthrie
Importantly, the prefabricated nature and low weight of timber elements has been found to result in incredibly safe sites. With a supervisor to worker ratio many times higher than experienced with larger structure workforces, no live edges, no high-risk trades, and on site cutting kept to a minimum, timber construction sites experience reduced occupational health and safety risks to all workers on site.
WOODSOLUTIONS’ ROLE The most important stage of a timber project is right at the start. It is important that timber projects are costed with the material, and what it means for a project in mind (this must also be considered in the design). If used correctly, timber construction can be faster, safer, quieter, and ultimately cheaper than traditional systems WoodSolutions is here to help this happen. The WoodSolutions Mid-rise Advisory Program team has offices in Melbourne and Brisbane. The team is available to provide free project-specific advice throughout all stages of a project. With expertise in costing, programming, engineering, planning, design, and construction, the team is well equipped to support you through your next timber project – simply contact us at info@ woodsolutions.com.au
THE BUILDING ECONOMIST - SEPTEMBER 2018 - 25
