Most of world's largest wooden structure The Grand Ring to be burned as "chips for fuel"

The Grand Ring in Osaka will primarily be converted into firewood, architect Sou Fujimoto has revealed to Dezeen.

Constructed to completely encircle the Expo 2025 Osaka site, which operated from April to October, The Grand Ring held the record as the world’s largest wooden structure. It spanned two kilometres in circumference and covered more than 61,000 square metres.

Demolition already underway

Similar to other buildings constructed for the expo, The Grand Ring was designed with dismantling in mind. However, authorities delayed determining its fate until after the event ended.

Demolition started at the beginning of December, with only a 200-metre section planned to remain intact.

In an exclusive interview with Dezeen, Japanese architect Fujimoto, who masterplanned the expo and designed The Grand Ring, explained that most of the remaining timber is expected to be incinerated.

“Unfortunately now, almost a decision by the political people [has been made about] keeping only 10 per cent, 200 metres, and then all the rest will be demolished,” he said.

“And then maybe 20 per cent could be carefully dismantled and then transported to other places for the second life,” he continued.

“But 70 per cent, at least as far as I’ve heard, they will just demolish and then make it chips for the fuel.”

The Grand Ring by Sou Fujimoto Architects at Expo 2025 Osaka — Authorities have not yet confirmed the future of The Grand Ring’s wood, but Fujimoto expects as much as 70 per cent to be incinerated

The final destination of The Grand Ring’s timber remains undecided by Expo and Osaka authorities, and Fujimoto’s studio is not involved in these decisions.

Before the expo concluded in October, The Japan Times reported that a city of Suzu official stated timber from The Grand Ring would be donated to help build public housing as part of the recovery following an earthquake and severe flooding in 2024.

The Japan Association for the 2025 World Exposition held an auction for the structure’s lumber from 17 October to 6 November. Its Sustainability Action Plan committed only to reusing materials “as much as possible”.

“Worst thing to do”

Fujimoto described the plan to burn the wood from The Grand Ring 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. But at least so far in Japan, the thinking of the sustainability is a little bit behind the global standards,” he continued.

“It’s a bit [of a] pity. [There are] still many opinions about how can we keep it or something, maybe discussion is happening, but major political decision has been done, and now the process is going on to dismantle.”

The Grand Ring’s structure blends modular modern construction with traditional Japanese techniques, such as Nuki joints, where a horizontal beam is slotted through a vertical post.

This approach allows for straightforward removal or replacement of damaged or weathered components and has been used in Japan’s oldest surviving structures, including temples and shrines.

Such techniques also make it possible to dismantle the structure easily and transport or rebuild it at another site.

Architect hoped the Grand Ring “could stay longer”

Fujimoto explained that, although he was aware the Osaka authorities intended the expo site to be temporary, he hoped the design would encourage the preservation of The Grand Ring.

“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. 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.”

Fujimoto estimated that with a canopy to shield it from the elements and adequate maintenance, The Grand Ring could have lasted “more than 50 or 100 years”.

“If they decide to keep it then 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.

“But still I believe it is possible to make it stay longer, for example more than 50 or 100 years, because as you know, in Japan we have several really long-lasting wooden constructions – some of them are more than 1,000 years [old].”