Five of the most high-profile wooden building projects in progress

With its sleek glass and steel frontage, to most passersby, the 25-storey Ascent building in Milwaukee in the US state of Wisconsin looks like many other luxury apartment towers.

However, inside the 259 apartments which overlook the city’s East Town neighbourhood, it quickly becomes clear that this skyscraper is (at least partly) made from wood.

At 86.6m tall, the building, which was completed in August 2022, has been recognized by the US-based Council on Tall Buildings and Urban Habitat (CTBUH) as the world’s tallest timber concrete hybrid building.

The structure comprises a five-storey concrete parking garage below 20 residential floors constructed using a system of beams made from glulam – a type of structural engineered wood lumber bonded together with adhesives.

Mass timber, also known as engineered wood, is comprised of layers of compressed wood which create strong, structural load bearing elements which can be structured into panelised components. It is designed to have the strength of materials like concrete and steel but is significantly lighter in weight and carries a lower carbon footprint.

The Ascent building is one of hundreds of new construction engineered wood-based projects being built around the world as architects search for ways to reduce the amount of carbon and steel included in new buildings.

Scientists say that by growing more trees to use in construction, humans can increase the amount of carbon they takes out of the atmosphere and store. Moreover, replacing elements of wood or steel buildings with wood also means that the buildings become more energy efficient. 

According to an assessment of mass timber construction published recently by the Environmental Coalition on Standards, making a building out of mass timber rather than traditional materials can reduce its lifetime carbon emissions by 50% or more. It found that  if mass timber construction became widely adopted by 2050, annual carbon storage could be as high as 700 million tonnes of carbon instead of just 10m tonnes.

“The advantages of wooden buildings are many, both for the environment and for people’s health and well-being,” says Annica Ånäs, CEO of Swedish developer Atrium Ljungberg, which is currently attempting to build Stockholm Wood City, the world’s largest wooden construction project. “As shown by various research studies, wooden buildings provide better air quality, reduce stress, increase productivity and store carbon dioxide throughout the time they are in use.”

Last year the CTBUH totted up a list of 139 mass timber around the world of eight storeys or higher which were either complete, under construction or proposed. And since then, even more innovative buildings incorporating mass timber – both high rise and low rise - are coming out of the woodwork.

Here International Construction takes a look at five of the most high-profile wooden building projects which could transform modern construction.

1. Atlassian HQ, Sydney

A new Australian HQ for tech company Atlassian currently being developed by property developer Dexus. The main contractors are Australian contractor Built and Japanese contractor Obayashi. Construction work started in August 2022 and is expected to be completed in 2026.

When completed the 42-storey tower, which will be built using mass timber concrete and steel, is set to become the tallest hybrid timber structure in the world.

The hybrid tower is expected to reach a height of 182.6 meters.

Located next to Sydney’s Central Station and forming part of a new Central Place Sydney project, the building targets a 50% reduction in embodied carbon and energy compared with conventional construction.

The tower’s hybrid timber megastructure is comprised of a concrete core with structural steel mega floors at every fourth level. Between these steel megafloors, three office levels will be built of mass timber. From level seven up, the structure is encased in a steel exoskeleton that cantilevers over the narrow building footprint.

2. Stockholm Wood City, Sickla, Stockholm, Sweden

Stockholm Wood City. Image: Atrium Ljungberg AB

Earlier this year, Atrium Ljungberg, a Swedish developer, unveiled plans to build the world’s largest wooden construction project.

Stockholm Wood City will cover more than 60 acres in the Sickla area in south Stockholm, comprising a total of 250,000 square meters. The project will include 2,000 homes and 7,000 office spaces as well as shops and offices.

Groundbreaking is set for 2025, and the first buildings in the district are scheduled to open in 2027.

3. Cincinnati Public Radio HQ, Ohio, USA

Cincinnati Public Radio is currently developing a new 35,000-square-foot building in Evanston in the city centre which will be the first two-storey mass timber building in the Midwest of the USA.

Rendering of CPR’s new HQ. Image: Skanska

When completed in late 2024, the $32 million building will feature two on-air studios, two interview studios, one performance studio, 11,000 square feet of office space and a public gathering area.

Swedish contractor Skanska broke ground on the project in August 2023.

The HQ’s entire column and beam structure, second floor, roof structure, as well as a selection of interior shear walls and exterior perimeter walls will be made from mass timber which the radio station says possesses superior acoustic qualities to concrete and steel.

“Mass timber projects are gaining traction throughout the country, including the heartland,” says Dean Lewis, director of mass timber and prefabrication at Skanska. “While most mass timber projects are hybrids, in which the lateral system is comprised of steel or concrete, this project’s lateral system is composed of cross-laminated timber shear walls, making it an almost complete mass timber superstructure.”

4. Rocket & Tigerli, Winterthur, Switzerland

Swiss real estate company Ina Invest is developing the 100 meters tall ‘Rocket’ tower in the Swiss city of Winterthur. The project, which will be built by Implenia is due to break ground in January 2024 with completion scheduled for June 2027. Implenia said that the timber element of the project would be made of wood composite flat slab (HVFD), a wood composite material which joins together to form a high-performance slab system. Implenia says that HVFD is 35% lighter than a conventional concrete floor, meaning that not as much concrete needs to be used in the foundations of the building and reducing GHG emissions from the shell of the building by up to 40%.

5. W350, Tokyo Japan

The Japanese wood products company Sumitomo Forestry Co is proposing to build a 350 metre (1,148ft), 70-floor tower to commemorate its 350th anniversary in 2041.

Unveiled in 2018, The new building will be predominantly wooden, with just 10% steel. Its internal framework of columns, beams and braces – made of a hybrid of the two materials. The interior structure, with 455,000 sq m of floor space, will be made entirely of wood.