Circulating resources

Until now, economies have been based on a linear model (one-way) in which things are made, used, and ultimately disposed of. However, environmental efforts have become a social necessity, so we have been promoting 3R activities, which include reusing what was once considered waste as resources to create and use things. Unlike the linear economy, which is premised on the generation of waste, the future will require the practice of a circular economy with things being made using as few resources as possible from the beginning and designed to prevent waste even after their purpose has been completed. Takenaka Corporation is pursuing a new way of thinking about society and architecture based on the idea of a circular economy.

Our efforts to date

In order to realize a circular economy, it is necessary to develop new technologies and transform the supply chain. Takenaka Corporation is promoting activities with the goal of reducing waste 50 percent by 2030 and 100 percent by 2050.

We have put forth the concept of Circular Design-Build in order to realize a circular economy, and we will promote initiatives to reduce waste, such as reuse, recycle, and upcycle, with the keywords of “make,” “use,” and “connect” instead of the conventional scrap and build.

The International Media Center*, a temporary building that will be demolished six months after construction, was designed and constructed in such a way that construction materials generated after the building's demolition can be thoroughly reused or recycled. As a result, 99 percent of the building materials were reused or recycled.

In order to reduce the amount of waste generated during the ZEB renovation work of our Higashi-Kanto Branch, we reviewed the areas scheduled for renovation to see if there were any parts that could be used without being demolished. This allowed us to reuse existing ducts, refrigerant piping, carpet tiles, external fins, and other parts. We also compiled a list of glass and other removed materials that would become waste, examined recycling, and recycled all of them. In addition, batteries from electric vehicles are being reused for the energy storage system in the ZEB conversion. In the end, we completely reduced CO2 emissions to zero with none during construction and none during operation.

Our construction project offices are working with intermediate processing companies in various locations to perform detailed sorting of materials generated during construction in order to recycle as much as possible. As a result, even though a large amount of waste material is generated along with increases in construction, the recycling rate always remains at 90 percent or more.

In culturally valuable buildings, such as historic ones, reusing existing tiles rather discarding them has great significance in preserving and passing on their historic design value. Rather than simply discarding tiles when rebuilding or renovating, we have developed a technology called MoltorⓇ that makes use the existing tiles to bring buildings back to life as attractive vintage buildings. By utilizing this technology, we are able to renew buildings without changing their ambience, which enables customers to use them as they wish for a long time.

In response to the global problem of waste plastics, the Act on Promotion of Plastic Resource Recycling was enacted in 2022. At Takenaka, we are investigating and getting to know the composition and processing situation for waste plastics discharged from our work sites, and we are examining separation methods for recycling.

Buildings are made up of many materials, and we are endeavoring to recycle as many of these as possible. Toward this end, we are working together with glass manufacturers to experiment on producing new glass from that removed at demolition sites.

In addition to our traditional business model of design-build, Takenaka is also promoting the utilization of historically valuable buildings as businesses in themselves. These projects take shape through our understanding the context of towns in each area locality, urban and rural.

This is a preservation and utilization project whereby a Spanish-style mansion built in 1927 was master leased and converted into a membership-based business innovation center while making the most of the charm of the existing architecture. In 2018, it became a national Registered Tangible Cultural Property.

A 200-year-old former sake brewery in Narai-juku, Shiojiri City, has been renovated into a small complex that includes an inn, restaurant, hot spring facility, gallery to promote local culture, and a sake brewery. Using locally produced wood and a variety of crafts, such as lacquer, which have been passed down in the area, and under regulations for preserving the external appearance and structure, we improved earthquake resistance, the thermal environment, disaster prevention, and sound insulation functions. In 2020, we entered into a partnership agreement with Shiojiri City with the aim of contributing to the creation of a sustainable society and resolution of local issues.

Under our Forest Grand Cycle concept, Takenaka has been developing and applying technology for mid- to high-rise wooden structures. This initiative is not only aimed at increasing the number of wooden buildings in urban areas, but also at resolving problems for maintenance and management of local mountain forests, which have become a social issue, by creating a new economic cycle between these forests and cities through the utilization wood. In 2022, we concluded an Agreement on Promoting the Use of Wood in Buildings with the Ministry of Agriculture Forestry and Fisheries, and we have since been accelerating the use of domestic timber in mid- to high-rise wooden buildings.

We are developing technology to convert residual food, large amounts of which are often discarded by food factories and restaurants, into energy through methane fermentation. By decomposing food waste inside buildings, without any need to transport it away, and generating methane gas, we are achieving a circular economy where energy is produced and consumed locally.