Up to 70% of the timber used in Osaka’s Grand Ring — the world’s largest architecturally designed wooden structure — will be turned into firewood, according to its architect Sou Fujimoto. That is despite Wood Central previously reporting that the vast majority of recycled timber would be used to build quake‑proof disaster housing.
The two‑kilometre‑long ring wrapped around the Expo 2025 Osaka site from April to October. Now, demolition is underway, with only a 200‑metre stretch slated for preservation as a long-term monument to the site.
Earlier this year, Wood Central revealed Fujimoto’s belief that the project was “a symbol of our times,” rooted in Japan’s centuries‑old wooden‑building tradition. “However, we haven’t fully harnessed these natural materials to their greatest potential. (As a result) I have blended traditional design principles with cutting‑edge tech to create the largest wooden structure.”
Around 70% of the timber used in the Ring was made of Japanese cedar and hinoki, while the remainder included stronger European red cedar and reinforced steel. Consequently, the structure was engineered to withstand major earthquakes. Inside, thousands of components were joined using Nuki joints — a traditional Japanese method requiring no nails or screws. Because of this, the entire structure could be dismantled and rebuilt elsewhere.
“Inside, massive wooden beams hold up the sloped roof, which doubles as the skywalk, protecting thousands of visitors from the weather,” said Andrew Dunn, CEO of the Australian-based Timber Development Association, who led a study tour of the World Expo site earlier this year. “From the highest point, you can take in the complete circular form of the structure, with pavilions from around the world gathered both inside and outside the ring.”
However, speaking exclusively to Dezeen overnight, Fujimoto said he now expects most of the timber to be burned. “Unfortunately, now, almost a decision by the political people [has been made about] keeping only 10%, 200 metres, and then all the rest will be demolished,” he said, before adding that “maybe 20% could be carefully dismantled and then transported to other places for a second life.” But he warned that “70%, at least as far as I’ve heard, they will just demolish and then make it chips for the fuel.”
Expo and Osaka authorities have not confirmed the final plan for the dismantled timber. Nevertheless, Fujimoto’s studio is not involved in the decision‑making.
Before the expo closed, The Japan Times quoted an official from Suzu saying some wood would be donated for public housing after the 2024 earthquake and floods. Even so, the Japan Association for the 2025 World Exposition auctioned off portions of the lumber between 17 October and 6 November.
Its Sustainability Action Plan is committed only to reusing materials “as much as possible.” Yet Fujimoto has slammed the burning plan as “the worst thing to do.”
“Japanese political people think this is one of the ways to reuse it, but I don’t think it is the way you reuse it,” he said. “But at least, so far in Japan, the thinking on sustainability is a little behind global standards.”
“It’s a bit [of a] pity,” he added. “There are still many opinions about how we can keep it or something, maybe a discussion is happening, but a major political decision has been made, and now the process is going on to dismantle.”
Fujimoto said he hoped the structure’s adaptability would convince authorities to preserve it. “I was hoping, I was expecting, from the very beginning that if the expo was very successful and if people really love it, then this Grand Ring could stay longer, like the Eiffel Tower or like some other few examples of the expo building which is staying longer,” he said.
“And that was my attitude from the beginning,” he added. “Of course, as [a] professional architect, I was following the request from the client, but at the same time I was expecting to go beyond that.”
With proper maintenance, Fujimoto believes the structure could have lasted “more than 50 or 100 years.” However, he warned that “we need some kind of maintenance or reinforcement, and so it will cost.”
“And then of course it is exposed wood, so we need a kind of maintenance cost yearly, so that is always the difficulty,” he said.
- To learn more about the Grand Ring, which in March was awarded as the world record as the world’s largest wooden architectural structure by the Gusiness Book of Records, click here for Wood Central’s special feature. And to learn why engineers are now developing new shock absorbers that will help buildings bounce back faster from quakes, click here for Wood Central’s special feature.
