As pioneering projects in mass timber challenge the use of steel and concrete in
skyscrapers, are we looking at a new era of sustainable construction?
By Shivani V K
24 Dec 2023
The proposed C6 building in South Perth, Australia, will be the world’s tallest wooden building | Image
Courtesy: Grange Development
Western Australia is on the brink of hosting the world's tallest wooden building, a groundbreaking 50-storey, 191.2-meter-high structure coming up in South Perth that will house 200 living units. 42% of the “hybrid” building called C6 will be made up of timber, including its beams, floor panels, joinery and linings.
Approved by the city’s authorities in October, the Grange Development project aspires to be carbon-negative; it will utilize a combination of glued laminated timber (glulam) and cross-laminated timber (CLT), both of which are renewable, resulting in less steel and concrete used compared to conventional construction methods. The Melbourne-based architecture firm Fraser and Partners, who designed the building, also claim that the 7,400 cubic meters of timber that it will use could be replenished in just 59 minutes from a sustainably farmed forest.
42% of the “hybrid” C6 tower will be made up of timber | Image Courtesy: Grange Development
C6 joins a growing group of hybrid timber high-rises across the world, adding force to a revolution that is challenging the high-rise industry, which has seen little change since it first gained popularity in the 19th century. This includes software multinational Atlassian’s headquarters currently under construction in central Sydney, and Ascent, a luxury apartment and retail tower in Milwaukee, USA, which topped out in 2022.
Atlassian’s hybrid timber headquarters currently under construction in Sydney, Australia | Image Courtesy
SHoP Architects
These buildings use mass timber, a family of engineered wood products including CLT and glulam, which is gaining popularity as a sustainable alternative to conventional building materials due to its high strength, comparable to that of steel. Products like beams, columns, walls and roof elements can be made by gluing multiple layers of sawn timber together.
Unlike most other construction materials, mass timber sequesters or stores atmospheric carbon instead of releasing it, making it carbon-negative. It also offers the added advantage of coming in prefabricated elements, allowing for easy assembly on site. “Because of this, construction will be very quick,” said Michael Green, a Canadian architect and author of the book The Case for Tall Wood Buildings, in an interview to the Guardian in 2015 when he proposed a 35-storey wooden building in Paris. “Someday I’d like to make a building where all you need is a giant allen key to put it together.”
Oregon Forest Science Complex in Corvallis, USA, designed by Michael Green Architecture | Image by Josh
Partee, Courtesy Michael Green Architecture
A United Nations Environment Programme report released in 2021 found the construction sector responsible for around 37% of all CO2 emissions in the world. Concrete accounted for 8%, highlighting how the ubiquitous material is the key culprit in the industry. In this context, projects like C6 are working to prove that mass timber might present a credible alternative — a material as strong and as easy to use as steel and concrete but with a much lighter impact on the planet. It must be noted, however, that mass timber’s end-of-life emissions remain contested, chiefly because so few buildings have been constructed out of the material yet, leaving even fewer that have been demolished. Most of the material in use today is disposed off in landfills or incinerators with decomposition eventually releasing carbon back into the atmosphere.
Regardless, mass timber’s popularity as a sustainable and carbon-neutral material is
growing across the world as the climate crisis takes center stage. Indian architect Akshat Bhatt, who recently completed the first timber residence in the country, says that while mass timber offers a very viable solution, it will take time for the industry to embrace the change and master its use. Fraser and Partners seem to share that thought; they plan to open-source publish all technical materials from C6, aiming to educate, inspire and seek feedback from other architects and experts to catalyze innovation. “Our great hope is that it challenges the industry to do future projects better,” says F&P director Reade Dixon.
