Could a new and novel (to Australia) mass timber construction system be key to accelerating low carbon low-rise and mid-rise buildings?
That is the question posed by Dr Alireza Fini, Associate Professor at the UTS School of Built Environment, who has spent the past decade researching the commercialisation of prefabricated timber systems for new projects.
In recent years, demand for mass timber has surged across Australia, but until now, most projects have used cross-laminated timbers (CLT), glue-laminated timbers (Glulam) and laminated veneer lumber (LVL).
However, that could change thanks to a new project funded by the Australian government, which will, for the first time, explore how dowel-laminated timber (or DLT) can be used in low- to mid-rise construction projects Australia-wide.
Dr Fini and the UTS School of Built Environment are leading the $7.5m Commonwealth-funded project involving industry partners, which does away with glues, uses low-grade timber and, most importantly, could make lower-rise buildings more commercially viable.
Speaking to the Fifth Estate yesterday, Dr Fini said the choice to explore DLT came after visiting one of the industry partners in Switzerland – a small company that made complex and precise timber design manufacturing processes from a small village outside Berne.
Switzerland is the home of DLT, with manufacturers connecting hardwood dowels to softwood boards since the 1990s. Over the past 25 years, the method has become more widespread across Europe, with North American companies now looking to use automated systems to drill and insert dowels into the timber.
According to Dr Fini, these companies use the most extraordinary and complex equipment; he told the Fifth Estate to create the most unusual laminated timber systems he has seen.
So, what is DLT, and how does it differ from other mass timber systems?
DLT is made by stacking timber and securing it with hardwood dowels – and unlike CLT and Glulam, it uses friction rather than glue to keep the panels in place.
Used in columns and beams, it is more cost-effective than CLT and Glulam. According to Canada’s Department of Forest Products and Applications, it is “more structurally efficient than CLT for one-way spans because all the boards face in the same direction.”
DLT uses a range of graded timber species, including Spruce-Pine-Fir, Douglas-Fir, Yellow-Cedar and Western Redcedar, “creating a panel that allows for flexible architectural design.”
Large panels can then be pre-manufactured for floors, walls and roofs – and can measure up to 3.7 metres by 18.7 metres, depending on shipping restrictions.
Without metal fasteners, CNC machines can easily automate DLT manufacturing with highly durable material housing pre-integrated acoustic materials, electrical conduits, and other service interfaces.
