The Resilience of Unfinished Architecture: A Life Cycle and NetZero Approach to Adaptive Heritage Reuse

The need to transition away from fossil fuels to a clean, circular, low (zero) carbon society is a global priority, and, to date, more and more countries are taking action to improve their future and environmental ecological, social and economic well-being. The built environment has a significant impact on many sectors of the economy, requires large amounts of resources and accounts for about 50% of all materials extracted. The construction sector is responsible for more than 35% of the EU's total waste generation; GHG emissions from materials extraction, manufacturing of construction products, and construction and renovation of buildings are estimated at 5-12% of total GHG emissions; improved material efficiency could save 80% of these emissions; and to increase material efficiency and reduce climate impacts, new comprehensive strategies for a sustainable built environment are needed, strategies that aim to safeguard natural resources, maximize bioclimatic and energy performance, and promote principles of circularity throughout the life cycle of buildings. Within this framework of references, unfinished architectures are among the elements of the built environment with great potential from the perspective of resilience and climate neutrality: they constitute a material resource since they are interrupted at a more or less advanced stage of construction, i.e., they have been abandoned or are awaiting completion. They realize a recurring constant in the history of architecture, giving rise to intense debates about the appropriateness of their completion and possible second life. Starting from the research objective of analysing the potential of the unfinished architecture from the perspective of climate neutrality, the paper reports the outcomes of research activities that aim to support a "normalized" definition of unfinished architectures, based on nationwide analyses and estimates, evaluating, different adaptive approaches for circular reuse from a Life Cycle and NetZero (zero soil-energy-CO2-waste) perspective, which are crucial for adaptation and mitigation of the causes of climate change, guiding the transition of existing, unused and unfinished architectural heritage to an “ecologically resilient” condition. The research led to the outline of an adaptive approach, which considers different intervention actions to operate on the existing skeletons, verified in several contexts, to validate a system of intervention lines that define compatible, adaptive and bioclimatic second-life technical elements, transferable to constructively different architectural structures.