World Expo’s Giant Roof: Osaka’s Massive Timber Ring Rises Fast!

Exclusive: The fabricators behind the world's largest timber will present at TimberConstruct.

Sun 19 May 24


With less than 11 months to go before Expo 2025, the construction of Osaka, Kansa’s ‘giant roof’- on its way to becoming the world’s largest timber structure – is rising at rapid speed.

Designed by Sou Fujimoto, the scale of the all-timber roof is out of this world – with a 2 km circumference, a 20-metre height, and an 8-metre walkway, the 60,000 square metre “wooden ring” is the centrepiece of the “dream island.”

“The design is meant to evoke a sense of Unity in Diversity,” according to Mr Fujimoto, who last month told Archinect that the design drew inspiration from the Kiyomizu template in Kyoto – known as Temple of the Pure Water Spring, one of the world’s most famous Buddhist temples.

“I want people to feel that this one sky is connecting all parts of the world, which is full of diversity as is shared by everyone,” he said, adding that the design showcases “the future of wooden architecture to the world and Japan.” 

On Monday, the Expo 2025 Osaka Kansai official website provided a construction update about the 60,000 square metre giant mass timber roof. (Photo Credit: Expo 2025 Osaka Kansai Official Twitter)
Last month, the Expo 2025 Osaka Kansai official website provided a construction update about the 60,000 square metre giant mass timber roof. (Photo Credit: Expo 2025 Osaka Kansai Official Twitter)

Mass timber construction is rising across Japan, with planning authorities reporting 36 planning applications for mid-rise and high-rise timber buildings last year alone—double the previous year. This comes as the Fumio Kishida-led Liberal Democratic Government is targeting timber-led construction to reduce carbon emissions and tackle a pollen-led public health crisis—billed as a “win-win.”

According to Andrew Dunn, Timber Construct organiser, Japan is leading the way in timber-led construction. Japanese-owned conglomerates are building giant build-to-rent projects in Australia, the US, and Europe using mass timber construction systems.

“Starting with the Tokyo Olympics (in 2021) and more recently with the World Expo in Osaka, what we are seeing coming out of Japan is remarkable,” Mr Dunn told Wood Central. “This is why we are thrilled to have Yuichi Shinohara, from Shinohara Shoten Co Ltd, who will speak at Timber Construct.”

“Shinohara Shoten is the timber fabricator that helped build Toyko Olympic infrastructure, and more recently is working on the World Expo,” Mr Dunn said, adding that Mr Shinohara will join Nick Milestone (from Mercer USA) and Xu Fang (from SEC/APA/SFPA in China) to discuss Australasia and the Pacific Visionary Timber Projects.

Screenshot 14 5 2024 155134 fotor 20240514155427 1
The “giant roof” under construction – Wood Central understands that timber will be used extensively throughout the 161 pavilions and exhibitions at the Expo. (Photo Credit: Sou Fujimoto Construction, via @sou_fujimoto/Instagram)

“So far, we have 39 presenters already lined up,” Mr Dunn said, including Duncan Mayes, the founder and principal of Finnish-based Lignutech Oy, who yesterday told Wood Central that future engineered wood products “are everywhere.” 

“Industry is now integrating cellulose from wood into cement, used in concrete structures,” Mr Mayes said, adding that “lignin may also reduce the amount of corrosion susceptible steel needed to reinforce the concrete.”

Mr Dunn said TimberConstruct, Australia’s largest timber construction conference and exhibition, will be held in Melbourne on August 12th and 13th, 2024, and “is focused on materials and design, prefabrication, and building techniques.”

“Early bird tickets are now on sale,” Mr Dunn said, “secure your early bird tickets before it is too late.”

  • Wood Central will have exclusive interviews with the panellists and presenters at TimberConstruct in the coming weeks.


  • Jason Ross

    Jason Ross, publisher, is a 15-year professional in building and construction, connecting with more than 400 specifiers. A Gottstein Fellowship recipient, he is passionate about growing the market for wood-based information. Jason is Wood Central's in-house emcee and is available for corporate host and MC services.


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