Buildings and construction are responsible for 39% of global carbon emissions, while construction works and materials alone represent 11%. Although great strides have been made in the operational energy efficiency of buildings, there is a growing concern for embedded or upfront carbon - all that goes into material extraction, processing, transportation, and construction works. Construction materials account for half of the raw materials used in Europe, while construction and demolition waste represent 1/3 of all waste - one of the largest waste fractions by volume in the EU. Building materials, therefore, show an enormous untapped potential for a circular economy.

The city has allowed small social enterprises to reclaim components such as doors and products from public social services buildings being demolished. Though the city is willing to give away materials for now, a legal barrier identified is that only persons permitted on demolition sites could be allowed into the building. In the future, the city hopes to sell revalorised materials from demolition sites.

Through various circular demolition pilot projects, experience shows the most straightforward way to ensure feasibility of reuse of materials is to minimise changes of ownership. The municipality of Oslo keeps a database of the planned and ongoing demolitions in the city - including public and private projects, which the city can influence through demolition permitting. This database allows city architects and project managers to consider those sites as material banks and include reclaimed materials in plans for new construction or renovation projects.

Due to the timeline and complexity of construction projects, access to information on upcoming demolitions in advance is fundamental to allowing inclusion of reclaimed materials in designs for new uses.

Until a stable market exists, giving materials away is still a cost-saving for the municipality, as they pay less for demolition works and waste treatment. Selling the materials is hindered by a need to certify their quality, which causes an administrative burden reduction. Consequently, and given the large public real estate portfolio, the city building agencies aim to include recovered building materials in their own renovations and new constructions.

Photo by Gunnar Ridderström on Unsplash