Biobased Building Materials' Contribution to a Circular Economy

Abstract

This explorative thematic case study investigates how biobased building materials can contribute to a more circular building industry. The case study focuses on straw and hemp insulation, exploring three core themes: (1) the suitability and technical performance of hemp and straw as insulation materials, (2) the impact these materials have on circularity in buildings, and (3) the main factors influencing the economic viability of straw and hemp insulation, including strategies to overcome identified barriers.

The theoretical framework for the research study integrates concepts from existing literature and research on building materials based on straw and hemp. Combines widely recognized circular economic principles and concepts such as the 4-R framework, waste hierarchy and biological resource cycle with a material circularity systematic assessment system to study the materials contribution to circularity. Circular solutions need to be economically viable to realize its potential in circular contribution. In combination the core themes cover the potential of straw and hemp insulation in contribution to a more circular building industry in practice.

Despite their environmental benefits and renewable nature, significant risks and barriers hinder the widespread adoption of straw and hemp insulation in Norway. Best case scenario for these materials requires appropriate waste streams for agriculture, and the current value chain is not optimized for their production and resource supply. Moreover, the lack of industry familiarity and verified technical performance standards makes these materials likely non- viable for large scale use. At present this limits them to niche projects such as environmentally friendly homes or showcasing pilot projects. However, with increasing regulatory emphasis on sustainability and circularity, both in Norway and the EU, there is clear potential for these materials to contribute to a more circular economy. Ultimately, straw and hemp insulation materials show promise for contributing to a circular building industry, provided that these initial barriers and threats are addressed.