Weighing up whether to construct a commercial building in timber, versus steel or concrete,has involved a lot of guesswork – until now.
An extensive research project based on a real-life, landmark new timber build has come up with a thorough cost and construction time comparison of the three structural materials.
Those heading to this month’s World Conference of Timber Engineering in Auckland will get a chance to hear all about these findings, including the emergence of engineered timber as a proven, viable option to steel and concrete.
Undertaken for the (then) Ministry of Agriculture and Forestry (MAF), the project looked at the initial cost, life cycle cost and time of construction for the new three-storey timber Arts and Media Building at the Nelson Marlborough Institute of Technology (NMIT).
Completed in 2011, the building uses the EXPAN LVL post-tensioned timber building system. The timber analysis was then compared with using concrete and steel as the main structural component.
The study showed that the NMIT building was cost competitive to build in timber.
After its involvement in the project, leading project delivery company Arrow International, confidently predicted that future timber multi-storey buildings will be at least as fast to construct as those in steel or concrete. And the full lifetime cost of a timber-multi-storey building was also shown to be at least as competitive as using other structural materials.
Having a real build to analyse was key to obtaining quality data, says the co-author of the paper on this work, Sustainability Researcher at the University of Canterbury, Stephen John.
“Providing detailed cost estimates and material schedules for a large-multi- storey timber building has previously been a challenge, with a scarcity on information due to such few buildings being recently completed in New Zealand.”
“It’s also impossible to guess issues that may arise during the building process. Being able to follow that entire process and track where additional costs were incurred, or extra time was spent, was crucial to coming up with fair and accurate comparisons.”
Involving independent industry professionals– all leaders in their field - also went a long way towards providing fairness, he says.
Along with the important material comparisons, the project has highlighted significant things for designers to consider when using large LVL elements as a structural material, and key points in the construction process and construction techniques which could reduce cost and time of construction of future, similar multi-storey timber buildings.
The research will serve as an important blueprint for investors, engineers, architects, quantity surveyors and builders, Stephen says.
“We hope this scientifically-based independent study will help decision makers with critical choices around constructing a new building, and assist in better costing and smarter construction of future timber buildings.”
Further research is focusing on a comparison of structural materials in a typical corner-site commercial building in Christchurch.
Stephen John will present the paper he jointly wrote with Professor Andrew Buchanan,‘Cost and Construction Time for a 3-storey Post Tensioned Timber Building Compared with Concrete and Steel Buildings’ on Wednesday July 18th at The World Conference of Timber Engineering in Auckland.
Visit www.conference.co.nz/wcte2012 for more.
"... future timber multi-storey buildings will be at least as fast to construct as those in steel or concrete. And the full lifetime cost of a timber-multi-storey building was also shown to be at least as competitive as using other structural materials. "
When combined with the other advantages this makes for a compelling argument for choosing timber construction.
THE NMIT BUILDING ON WHICH THE STUDY WAS BASED.