6th International Holcim Awards for Sustainable Construction

The project describes a building extension in which the added floors are designed to utilize the demolition waste from other construction sites. An industrial building in Winterthur, Switzerland will be repurposed to create a series of 12 units/studios. The design process starts with the collection and classification of building elements sourced from dismantling and demolition operations, and the identification of their potential for recycling. An external steel staircase, aluminium windows, metal corrugated sheets, roof insulation and photovoltaic modules are all salvaged from previous construction and given a second life. Steel beams are reused for the new structure, old façade stone cladding is redeployed as floor tiles.

Wherever it was not possible to reuse old building elements, the architects opted for natural materials including wood for structural components, straw for the wall insulation, and clay for the interior plaster. The recycling operation and adoption of low-impact materials reduces the embedded carbon footprint by about 60% compared to traditional buildings. Constructed so as to be easily disassembled in the future, the proposed design allows for further recycling in the future. To maximize energy autonomy, the project considers the integration of solar systems on the roof to meet operational energy requirements.

The problem of construction is also a problem of demolition – which is especially the case in Europe where space is cleared for new buildings. The project team redefines the starting point of the design process: and turns demolition waste into a construction opportunity. The Holcim Awards jury Europe considered the project to exemplify a paradigm shift in sustainable construction for its systematic technique that enables the direct re-use of building elements, thereby showing how to dramatically diminish the environmental impact of the construction sector taken as a whole. The revolutionary approach to design is cleverly reconfigured: it starts with a very rational analysis of recyclable materials available locally and then builds the project from it, while still being able to produce a very original and unexpected architecture. In this sense, the jury admired the way the project shifts our understanding of aesthetic impact and beauty. The project supports the notion of a circular construction industry, providing a thoughtful sustainable solution also for the post-use phase of the building.