Mass timber construction (MTC) is a building process which uses large sections of engineered wood for the primary building structure. Emphasise the word process. MTC is about much more than materials. It is a whole new way of thinking about construction.
Historically, within Australia and New Zealand, engineered wood products have mostly served the low rise residential sector. (The exception is long-span Glue Laminated Timber Glulam.) More recently, developments in re-engineering raw timber have brought Laminated Veneered Lumber (LVL) and Cross Laminated Timber (CLT) into the realm of commercial construction.
Along with Glulam, these products are now being used, either combined or individually, to compete with traditional steel and concrete in commercial buildings, or often to work effectively with them in hybrid structural solutions.
There are many drivers for mass timber buildings. Wood stores carbon. The most effective tool for carbon removal from the atmosphere is a tree and trees are renewable. Construction costs compete on labour savings. Building with off-site prefabricated mass timber components is faster, safer and more precise. Damage remediation in timber buildings is simpler. Wood has aesthetic appeal and proven health values. And the whole of life cycle costing is lower.
We know now that, for some building types, it can be more economical to build with mass timber.
In a 2015 report undertaken by the Australia Forest and Wood Processors Association (FWPA), research teams including Arup, AECOM, Studio 505, Fitzpatrick + Partners and Building Cost Information System (part of the Royal Institution of Chartered Surveyors) provided comparative costings for timber against more conventional concrete framed or steel framed buildings in an urban location.
Mass timber solutions were found to be cheaper than conventional steel and concrete framed construction by 12.4% for commercial buildings, 13.9% for aged care, 2.2% for apartments and 9.4% for portal framed industrial sheds. Building designs included analysis of heating, ventilation and air conditioning, facade and acoustic considerations.
Solutions were tested against available products, including CLT, LVL and Glulam, and existing supply chains for these products. No consideration was given to environmental benefits or life cycle savings. The report noted that other savings could be made on sites with poor ground conditions or where constrained access suited off-site prefabrication.