Buildings or developments that illustrate the principles of the circular economy in an exceptional way.
Canada’s 100-year-old parliament building, Centre Block in Ottawa, is undergoing an extraordinary retrofit that blends heritage conservation with sensitive contemporary interventions including seismic upgrades, modernized building systems, and new spaces to support parliamentary operations.
The project teams at WSP and HOK are going to great lengths to preserve and repurpose as much of the building’s existing fabric as possible. For example, as part of the seismic upgrades and the design interventions, approximately 500 metric tonnes of steel will be removed from the building and repurposed. Reusing steel has a significant environmental benefit over recycling. The re-melting and shaping of steel into usable members accounts for approximately 95% of steel’s embodied carbon.
Extensive testing, as part of the seismic upgrade process, demonstrated that the existing steel was structurally suitable for reuse. Approximately 200 tonnes will be reused within Centre Block, 200 tonnes will be made available for use by other projects within the Parliamentary Precinct, and any remaining steel will be repurposed on other projects or recycled. There was an initial assumption that deconstructing and reusing steel would be expensive. But following an in-depth review of the process and costs, it was determined to be cost-neutral and potentially cost-saving due the rising price of steel.
This reuse of steel is salvaging the equivalent of 1,250 tonnes of carbon emissions from the existing steel, in addition to reducing embodied carbon from new steel by approximately 120 tonnes. Conserving and reusing historic buildings is integral to a circular economy. This project demonstrates the importance of assessing the opportunity to reuse materials, not just recycle them, and the wider benefits this could bring.
