Construction begins on 'Grand Roof' in Osaka for Expo 2025

Visitors to the Expo 2025 Osaka will be able to walk on a 2km ring that ‘connects with the sky’

Construction has begun on a giant ring-shaped wooden roof at Expo 2025 Osaka's site. Expo 2025

Cranes lower timber frames as work begins to construct the world's largest wooden roofs for Expo 2025 Osaka. Photo: Japan Association for the 2025 World Exposition/ Obayashi Corporation

Construction work has begun to build a gigantic wooden roof at Yumeshima, a man-made island in southern Japan. Photo: Japan Association for the 2025 World Exposition/ Obayashi Corporation

Traditional construction techniques without using nails are being followed. Photo: Japan Association for the 2025 World Exposition/ Obayashi Corporation

The giant wooden ringed structure will take about two years to complete. Photo: Japan Association for the 2025 World Exposition/ Obayashi Corporation

The wooden frames beng lowered into slots demarcated in the foundation. Photo: Japan Association for the 2025 World Exposition/ Obayashi Corporation

About 20,000 cubic meters of wood will be used in the construction. Photo: Japan Association for the 2025 World Exposition/ Obayashi Corporation

Renders of the grand roof ring, billed to be the world’s largest wooden ringed structure. Photo: Japan Association for the 2025 World Exposition

The great ring roof will be covered with greenery and flowers and will offer a view of the Expo site below. Photo: Japan Association for the 2025 World Exposition

The wooden ring roof will be in the central area and connect with hundreds of pavilions constructed by countries and companies. Photo: Japan Association for the 2025 World Exposition

Visitors will be able to walk a couple of kilometres across the wooden roof. Photo: Japan Association for the 2025 World Exposition

The roof and surrounding areas are being set up for the 2025 Expo in Yumeshima, Osaka. Photo: Japan Association for the 2025 World Exposition

Visitors will have a grand view of the sea and the expo site. Photo: Japan Association for the 2025 World Exposition

Overhead view photo of Yumeshima, the site of the next World Expo. Photo: Expo 2025

Work has begun to construct a ring-shaped wooden roof on a Japanese island in the southern Osaka Bay area for the next World Expo.

The 2km structure, known as the Grand Roof, is being readied for the Expo 2025 Osaka, an event that will be held following the success of the Expo 2020 Dubai which drew more than 24 million visits in six months.

On Yumeshima, a man-made island, wooden columns are being winched into place by workers assembling the structure that will take two years to complete.

About 20,000 cubic metres of wood will be used in the construction, making it one of the largest wooden structures in the world.

The Japan Association for the 2025 World Exposition said the roof serves as a symbol of the Expo.

Without nails

The wooden ring is constructed using traditional Japanese techniques found in ancient temples without using nails to hold the timber in place.

Hiroyuki Ishige, secretary general of the association told the Bureau International des Exposition – which oversees the world fairs – that connection and unity were vital themes of the project.

“If you go up on to the grand roof, you can connect with the sky and see the ocean,” he said.

“The design symbolises the idea of unity in diversity.”

He said the roof would be the connecting point to view hundreds of pavilions belonging to participating countries.

The construction cost for the five-storey high structure is about 35 billion yen ($249 million).

Sharing one sky

When visitors walk on the roof, they will be able to have a bird’s-eye view of the World’s Fair site.

The wooden canopy will also protect visitors from the sun.

Sou Fujimoto, the architect of the roof, said the aim was to present a vision so people would see the future positively.

“I designed a large ringlike platform that people can walk on and this will make a link of people and cultures from diverse worlds,” he said in a video message.

“Here we share one sky above us.”

He promised a unique experience for visitors and said more information would be released about the plans in the lead-up to the event.

“It is a place where people from all over the world will unite their thoughts, respect each other and experience something special together,” he said.

“We hope to share our thoughts with all of you from all over the world about this site.”

Vantage points across the sloping roof will provide a clear view of the expo site and the sea.

Flowers and greenery will cover the 30m wide wooden structure that will range in height from 12m to 20m high.

A crescent-shaped waterfront zone, located on the south of the roof, will host events on the water.

The west of the site will be the stage for outdoor events and where best practices from different sectors can be presented in an open space.

Transforming communities is the subject the expo aims to explore with the theme “Designing future society of our lives”.

The expo will run from April to October 2025.

It will be the third Expo that Japan has hosted and the second such event for Osaka, which held Asia’s first World Expo in 1970.

The race to win the bid for Expo 2030 is already under way.

Saudi Arabia, Rome, South Korea and Ukraine have bid to host the event with a final vote in November in Paris.