USE OF BIO-BASED MATERIALS

1.1. DESCRIPTION Maximum circularity of materials is achieved when they are able to regenerate new virgin materials at the end of their life, not creating any waste, but rather being a new source of material. For this reason, the use of bio-based and natural materials, such as wood, bamboo and raw earth, is to be preferred, whenever possible, to materials that cannot be completely recycled, such as cement mixes. Once decommissioned, these materials are naturally biodegradable and can create compost for fertilising productive land. 1.2. RELEVANCE FOR CIRCULAR BUILDINGS The integration of these materials into buildings, whether for structural or non-structural purposes, aligns with the idea of waste prevention, i.e. with the principles of Reduce, Refuse and Rethink: with the choice of natural materials at the planning and design stage, the greatest benefits occur at the end of life, where instead of a loss of value as with technical materials, there is an increase in value as they contribute to the generation of new material. 1.3. INNOVATION ASPECTS Rather than an innovative approach, this is a return to more primitive and vernacular building techniques, which are undoubtedly more sustainable than those that have taken hold since the excessive industrialisation of the sector; however, materials of natural origin are now being researched and processed to maximise their benefits and performance, making them as good as traditional ones, with a continuous push towards innovation and the green transition. However, not all building components can be made exclusively from bio-based materials: for those sectors where this is not possible, there must still be an interest in identifying more natural solutions to increase competitiveness.

2.1. PRACTICAL APPLICATIONS - Use of natural and self-regenerating materials such as: bamboo, cross-laminated timber (CLT), solid wood, cork... - Dismantling the natural components in the building and using them to generate new material - Planting of woods and forests from which to draw material - Choice of bio-based materials also in function of a shorter supply-chain, using timber and other products available in abundance from the construction area - Reduction of treatments on natural materials to promote their composting - Use of bio-based polymers - Checking the environmental sustainability of the use of certain materials found in nature, especially in relation to the consequences on the ecosystems

3.1. BENEFITS - Absence of waste production because once the material is discarded it is biodegradable or can be composted - Contribution to the regeneration of the environment instead of only creating negative impacts - Good predisposition of such materials to prefabrication - Possibility of building lighter structures or, if used in combination with other structural materials such as reinforced concrete, of partially lightening very massive structures - Reduction of the embodied carbon of the entire structure - Simplified design, without the need for overly complex designs (this is referred to as low-tech design), particularly in the case of wood 3.2. COMPLEXITIES - Lack of regulatory support and/or adequate guidelines for designers for structures with these materials - Materials with shorter lifecycles than non-renewable materials such as metal and plastic, with the need for continual replacement that may in the long run be more impactful than the use of other materials - Reuse of these materials limited to down-grading - Risk of incorrect or mismanagement of forests and woodlands from which timber is obtained, especially in terms of biodiversity conservation and carbon sequestration - Greater vulnerability of these materials to weathering and subsequent degradation, requiring more frequent maintenance or replacement