Mass timber buildings
The benefits of mass timber construction has been utilised around the world for a number of years. Kevin Ezard looks at some local developments and the move into residential construction.
Current trends and future directions for residential and commercial buildings using structural timber and engineered wood construction systems are discussed at the Frame Australia conference every two years. The event remains a key feature on the calendar with delegates attending from the building and construction industry, and the timber, wood product and pre-fabrication industry.
At this year’s event in June, the building industry is announcing some outstanding initiatives that demonstrate remarkable progress for innovative thinking in construction methods, with one high-rise building already underway in Melbourne claiming the title of the world’s tallest apartment building using timber as the construction system.
This is a rapidly developing global trend, and in February this year the Canadian Wood Council released a case study project report The case for tall wood buildings which outlined how ‘mass timber’ offers a safe, economical, and environmentally-friendly alternative for tall building structures.
The report describes a new structural system in wood that represents the first significant challenge to concrete and steel structures since their inception in high-rise building design more than a century ago. The introduction of these ideas is driven by the need to find safe, carbon neutral and sustainable alternatives to the incumbent structural materials of the urban world.
The solutions proposed have the potential to revolutionise the building industry, and to address the major challenges of climate change, urbanisation, sustainable development, and to significantly contribute to world housing needs.
‘Mass timber’ is a term which includes several existing panel products in the market including Cross Laminated Timber (CLT), Laminated Strand Lumber (LSL) and Laminated Veneer Lumber (LVL),
The structural characteristics of mass timber that enables these high-rise solutions includes the fact that on a weight to strength ratio, engineered wood products generally match – and in some cases exceed – the performance of reinforced concrete. In addition, mass timber behaves very well in fire, and is significantly different in fire performance to that of lightweight timber frame.
At present, it seems the CLT construction system is becoming universally popular with architects and builders alike, and is being designed not only into high-rise developments but extensively into residential housing.
CLT is an extension of plywood technology and is often described as ‘jumbo plywood’ or referred to as ’tilt up timber’ or ‘pre-cast timber panels’ as a viable alternative to more traditional building practices.
Cross-laminating layers of timber improves the structural properties by distributing the along-the-grain strength of wood in both directions, and this means that CLT panels can be used to form complete floors, walls and roofs. It is a timber panel product that actually has similar characteristics to that of a pre-cast concrete panel, but is lighter than concrete, more easily worked and easier to erect.
Getting back to Australia’s first timber high rise modern apartment building and the tallest in the world, ‘Forte’ in Victoria Harbour at Melbourne’s Docklands is aspiring to be the first 5 Star Green Star residential building in the country, and will be more than 10 storeys offering 23 boutique residential apartments and four townhouses.
Designed and built by Lend Lease, the Forte building will reflect the contemporary inner-city lifestyle while combining environmental initiatives such as better energy efficiency in terms of heating and cooling, and will be a showpiece for natural and new, where modern architecture meets a natural building material.
Currently under construction, it will be the first building of its type in Australia using CLT, introducing a more efficient and environmentally-friendly process with adoption of green technologies, materials and construction processes.
Major developer Grocon is also using the CLT system in their planned ‘Delta’ building in Melbourne which will be one of Australia’s first Passive House certified buildings as part of a new breed of zero carbon multi-story buildings that use wood as a central building component.
The Delta 50-unit residential tower in Melbourne’s CBD will stand 10-12 storeys tall atop a heritage bluestone building, with a design closely connected with the new European model for mass timber construction to Passive House standards, which significantly reduces the requirements for heating and cooling to lower energy costs.
Grocon stated that they are also responding to the Federal Government’s carbon price applying from July 1 this year, and indicated their readiness for a new way of building as a carbon constrained economy is upon us.
There is no doubt that mass timber wood panel construction systems such as CLT have the potential to revolutionise traditional practices for residential and commercial building, in particular due to their lower site labour requirements and very fast construction times.
Another important factor is the vital need for greater energy efficiency in dwellings requiring higher quality of construction potentially to Passive House levels, which can only be achieved in the way the building is designed and manufactured.
This requires an airtight building envelope which is readily attainable from factory-built wood panels, and to be well-insulated to significantly improve the building performance to achieve low energy requirements for comfortable and sustainable living.
This topic and others are being presented at Frame Australia 2012 on June 18 and 19 at the Park Hyatt Melbourne, with program sessions covering green buildings and carbon, design and manufacturing software, building project data integration, engineered wood and structural timber, wood construction systems, and pre-fabricated frame manufacturing.
For more information visit the website www.frameaustralia.com