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

The Grand Ring in Osaka will be mostly turned into firewood, its architect Sou Fujimoto has told Dezeen.

Constructed to encircle the site of Expo 2025 Osaka, which ran from April to October, The Grand Ring was the largest wooden structure in the world, with a circumference of two kilometres and covering more than 61,000 square metres.

Demolition already underway

Like other structures built for the expo, The Grand Ring was designed to be dismantled, though authorities held off on deciding its future until after the fair concluded.

Demolition of The Grand Ring began at the beginning of December, with only a 200-metre section set to be retained.

Speaking exclusively to Dezeen, Japanese architect Fujimoto, who masterplanned the expo as well as designing The Grand Ring, said he expected most of the rest of the wood to be burned.

"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."

Expo and Osaka authorities have not yet confirmed what will happen to The Grand Ring's dismantled timber. Fujimoto's studio is not involved in the decision-making.

Shortly before the expo closed in October, The Japan Times quoted an official from the city of Suzu as saying that timber from The Grand Ring would be donated to build public housing as part of the recovery from an earthquake and severe flooding in 2024.

The Japan Association for the 2025 World Exposition ran an auction of The Grand Ring's lumber from 17 October to 6 November. The body's Sustainability Action Plan for the expo committed only to reusing building materials "as much as possible".

"Worst thing to do"

Burning the wood from The Grand Ring is "the worst thing to do", Fujimoto said.

"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 combines modular modern construction methods with traditional Japanese techniques, such as Nuki joints in which a horizontal beam is slotted through a vertical post.

This technique enables easy removal and replacement of damaged or weathered pieces, and has been used to build some of Japan's oldest existing buildings, such as temples and shrines.

It also facilitates disassembly of the structure, as well as easy transportation and rebuilding in another location.

Architect hoped the Grand Ring "could stay longer"

Fujimoto said that though he knew the Osaka authorities only intended for the expo site to be temporary, he hoped that by designing The Grand Ring in this way, it might be retained.

"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."

With a canopy to protect it from the elements and proper maintenance, Fujimoto estimated that The Grand Ring could have stood for "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]."

Fujimoto said that he disagreed with the policy of making the expo structures temporary.

"I feel it's a bit [of a] pity that they decided at the very beginning that the whole site should be temporarily built and then, after the expo, dismantling everything, or relocation of everything, and then make the another development on that site," he said. "That is not really a smart way to make that kind of a large development."

"But anyway, they decided to do that," he added. "And then my role was, anyway, to make, of course, great things for the expo."

The Grand Ring was recently selected by Dezeen deputy editor Cajsa Carlson as her favourite building of 2025.

Dezeen has approached The Japan Association for the 2025 World Exposition for comment.

The photography is by Lizzie Crook.

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