tprint for timber buildings from responsibly sourced wood compared to steel, concrete and aluminium counterparts (the low energy used to make the building materials means reduced embodied energy);
lighter: resource-reduced construction with only a quarter of the weight compared with a concrete building, and significantly reduced waste;
the ease and affordability of heating and cooling a CLT dwelling, providing a healthy indoor climate (resulting in reduced operational energy and smaller energy bills for residents).
In the 1970s, off-site manufacture of building components led to industrialized uniformity and monotonous architecture. But Building Information Modelling (BIM), using computer-aided calculation and production methods, allows for a diversity of individual solutions (mass-customization). Accurate off-site prefabrication of CLT panels enables modular construction and enhances the use of efficient, digital design techniques. CLT wall panels can be precision cut off-site to create window and door openings and in some cases are already fitted with insulation, external cladding and windows. Prefabricated panels are also used for floors, roofs, ceilings, lift shafts and stairwells in some multi-storey buildings [46,47,48]. The review of cases in the scoping study highlighted the rapid on-site construction that may be as short as three to four months for buildings of up to nine storeys . Such short construction times, compared to traditional multi-storey construction methods, reduce noise impact, the risk of accidents on-site and the need for traditional construction equipment such as fixed cranes. CLT systems provide a precise construction process that allows faster completion, increased safety on site, less disruption to the neighbourhood and less waste. Traditionally around 40 per cent of all solid waste comes from construction and demolition. These benefits are not, of course, limited to CLT buildings but will be part of all modern methods of construction that utilize prefabricated wall, floor and roof construction elements.
While there is currently no Australian manufacturing facility, mechanisms are in place whereby CLT panels can be supplied from Europe (at the time of writing companies in New Zealand and Canada have recently started to produce CLT panels; and Australian developer Lend Lease is considering establishing a domestic supply chain, based on radiata pine, with the aim to end the reliance on overseas products; personal communication with Lend Lease, 2012). Recent material testing has shown that the quality of pine in Australia can be considered equal to European spruce and NZ radiata.
The first CLT multistorey residential building in Australia is the residential tower at 807 Bourke Street in Victoria Harbour (Docklands) in Melbourne, built in 2012: a 10-storey apartment building constructed entirely in CLT panels by Lend Lease in collaboration with KLH (Austrian panel manufacturer). The construction period was short, from May to October 2012.
Having recognized the unsustainable nature of many current practices—such as using carbon-intensive materials such as reinforced concrete—we now have the opportunity through massive wood construction to develop more inherently sustainable approaches.
4. Examples of CLT-Constructed Buildings in an Urban Context: European Case Studies and a First Application in Australia
How can consumers be influenced to accept apartments constructed entirely of timber? The use of post-occupancy evaluation (POE) of new, affordable and sustainable housing projects is a promising approach for analysing occupant comfort, user behaviour and energy consumption. It will enable researchers to develop and validate an ‘ideal’ model for infill housing using CLT for Australian cities. Surprisingly, there have been few studies of housing using POE or studies that specifically assess whether the social aims of such developments are being achieved [49,50].
In Europe, construction of solid wood panel multi-storey apartment buildings has increased recently. Projects in European cities that have b