Obayashi Corporation and AGC Inc. announced on August 19 that they have established a closed-loop recycling flow in which waste window glass generated at Obayashi’s demolition sites is reprocessed into part of the raw material for AGC’s architectural float glass (flat glass produced by floating molten glass on a bed of molten tin). As the first application of this flow, waste window glass from the demolition of the Mitsubishi UFJ Bank head office building is being fed into the recycling process — a case that AGC’s research as of May 2026 confirms is the first of its kind in Japan.
The backdrop to this initiative is the construction industry’s challenge of reducing CO2 emissions across the entire lifecycle of buildings. Emissions arising from the manufacture, procurement and transport of materials, as well as from the construction phase itself, represent an area where construction companies have significant room to act, making the adoption of reused and recycled materials a priority. Obayashi has been progressively building closed-loop recycling flows for steel frame members reused between buildings (June 2024), steel scrap (November 2024) and aluminium scrap (December 2025); the current glass initiative is a natural extension of that effort.
AGC has been working with local governments and private companies to develop an end-to-end system covering the collection of waste window glass from demolition sites, intermediate processing, and the supply of recycled raw material (cullet). Mitsubishi UFJ Bank began demolishing its head office building in February 2025 in preparation for a new building scheduled for completion in October 2030, and contributed the waste window glass as part of its support for initiatives that reduce environmental impact.
In the Mitsubishi UFJ Bank head office demolition project, collected waste window glass is processed into cullet by an intermediate processor before being delivered to AGC’s Kashima Plant, where it is remelted into flat glass. The project will recycle a total of 149 tonnes of waste window glass — including material recovered for glass wool production — of which 81 tonnes will be closed-loop recycled back into flat glass, with an estimated CO2 reduction of 49 tonnes based on calculations by the Flat Glass Manufacturers Association of Japan. Conventional glass recycling has centred on producing patterned or wire-reinforced glass, but by using the recovered glass as raw material for general-purpose clear float glass, this approach makes it possible to scale the process across the entire architectural flat glass sector.
More than 500,000 tonnes of waste window glass are generated annually from buildings in Japan, yet the vast majority has historically ended up in landfill or been downcycled into lower-quality products. In March 2025, AGC established a closed-loop recycling scheme for window glass from residential renovation projects together with the Orix Group and TRE Glass Co., Ltd., and in April 2026 it achieved closed-loop recycling of window glass within the same building during a large-scale renovation project in collaboration with Taisei Corporation. Closed-loop recycling of flat glass is thus beginning to gain traction across the industry. The initiative with Obayashi represents a distinct application: waste window glass from a demolition site is used as raw material for float glass destined for other construction projects.
Obayashi and AGC intend to continue operating the flow they have established and to expand its scope, with the aim of further advancing the circular use of construction materials.
【Press Release】Japan First: Waste Window Glass from Building Demolition Sites Used as Raw Material for Float Glass
【Reference Article】Orix Group and AGC Establish Japan’s First Closed-Loop Window Glass Recycling Business Scheme
【Reference Article】Japan First: Closed-Loop Window Glass Recycling Achieved Within the Same Building — Material Recovery of Waste Flat Glass Generated During Renovation Works
【Reference Article】Flat Glass Recycling Vision — First Vision 2025
【Related Article】Sekisui House, Daiei Kankyo and AGC Conduct Japan’s First Pilot for Closed-Loop Recycling of Window Glass from Home Renovations
【Related Article】Orix and AGC Collaborate on Closed-Loop Window Glass Recycling
※ Images at the top and within the article are sourced from the press release.
※ The lead image shows the waste window glass recovery process at the Mitsubishi UFJ Bank head office demolition site.
