According to the United Nations Global Status Report for Buildings and Construction, the construction sector is responsible for approximately 40% of global CO₂ emissions (UNEP, 2022). Due to the linear design of the economic system, valuable building materials are disposed of at the end of their life cycle despite their high material value, instead of being kept in circulation. The reuse and dismantling of building components contribute significantly to reducing emissions.

For several years, materialnomaden GmbH has been contributing its expertise in circular economy to the construction industry through projects of various sizes. At the end of 2021, circular house GmbH was founded. It acts as project developer and builder for the LenA project. Using an extension to an existing building in a 1950s single-family housing estate in Upper Austria, the application demonstrates in a prototypical manner that high building quality, low resource consumption, and minimal emissions can be achieved through the principles of circular construction in both renovation and new construction projects. In this project, the existing building will be renovated and extended, and two additional independent units will be added to the property, bringing the total usable floor space to 360 m².

Accompanying the construction work, research and demonstration of the positive climate impact of reuse is one aspect of describing the new processes in a standardized way and transferring the main principles to the currently valid service phases in planning and execution.

An ecological comparative assessment—an LCA (Life Cycle Assessment) prepared by Team Exikon—shows the extent to which a ReUse building has a positive impact on people and the environment compared to a conventional new building.

The fact that reuse enables many times more resource savings than recycling is illustrated by the use and development of ReProducts®. ReParkett® – one of the first standardized reuse products – is used in the project. Thanks to its CO₂ certificate, quantifiable emission savings are included in the building assessment. This can be evaluated as a steering component for EU taxonomy-compliant project financing for bank loan conditions and illustrates the potential financial viability of a construction transition that will increasingly have to commit to existing buildings and secondary materials to achieve set climate targets.

The assessment of the secondary resources saved and reused requires the integration of the "demolition" phase: for the creation of the component database, this results in additional planning work that has not been considered in conventional planning projects to date. Digitalization and component cataloging play an essential role here in transferring information on availability, dismantling period, and quantity, as well as properties for integration into a new plan. RosinA is the tool used to create reuse data sheets. Components, materials, and products from demolished buildings or other sources that are suitable for reuse are recorded on site, supplemented with image, object, and material properties, and transferred to a database. The digitally available information on the respective potentials can be used to create component catalogs that serve as the basis for the further redesign process.

In addition to the ecological and economic project goals, there is great potential in social sustainability. In order to raise awareness and appreciation for what already exists, BASEhabitat (University of Art and Design Linz) is involved in the consortium. The project enables future architects to get involved in the process of dealing with a specific building, from inventory and deconstruction to design and conversion. Through practical work on the LenA construction site, architecture students gain hands-on experience and direct insight into working with renewable and circular building materials. The Camillo Sitte Bautechnikum (HTL Vienna) has been entrusted with inspecting and testing reused materials to ensure compliance with applicable building regulations.
All processes and findings are summarized in a compendium, the "Circular Architecture Rules," which can be used for holding further workshops and teaching courses on ReUse projects.

Project management

materialnomaden gmbh & circular house gmbh, Andrea Kessler

Project or cooperation partners

• Camillo Sitte Versuchsanstalt für Bautechnik Bautechnikum und Versuchsanstalt Wien III
• circular house gmbh
• EXIKON arc&dev
• Universität für künstlerische und industrielle Gestaltung Linz - RUD/die architektur/BASEhabitat

materialnomaden gmbh
Belvederegasse 14-16
Tel.: +43 (664) 5677474
E-mail: lena@circularhouse.eu
Web: http://circularhouse.eu