(CS3.2) Quantifying Embodied Carbon Emissions from Structural Interventions for Existing and Historic Building Reuse

This research investigates the embodied carbon emissions resulting from the structural intervention in historic and existing building reuse by analyzing case studies in New York and Connecticut. Historic buildings require structural intervention for various reasons, such as maintenance, repair, restoration, and reuse. These interventions are typically guided by design approaches based on numerous considerations, such as cost, constructability, and minimized intervention, amongst others. However, the carbon cost of the structural intervention is rarely considered despite the current climate crisis and the imperative to reduce carbon emissions.

This research explores the potential impacts of embodied carbon assessment utilized in design considerations for the structural engineering of historic and existing structures. This research compares carbon assessment methods to develop guidelines for practitioners and provide recommendations for future work in this study area. This research uses two methods to calculate embodied carbon: (1) the CARE Tool, a free online early design consideration tool that estimates and compares embodied, operating, and avoided carbon impacts, and (2) The Structural Carbon Tool manual calculation tool developed by Institution of Structural Engineers (UK). These methods are applied to four selected case studies in New York and Connecticut to compare the methods and develop data to improve existing estimation tools. The analysis results are assessed to understand the environmental impact of structural interventions, thereby providing insights that can inform future structural decisions to minimize carbon footprints. Further, embodied carbon estimations for structural renovation of a historic building can be used in competition with estimations for new construction on a square foot basis as a potential justification for building preservation and historic material retention.

In exploring the embodied emissions of completed projects of varying size, scope, scale of intervention, material, structural typology, and historic designation, this research highlights areas of significant potential impact. Further, through the comparative analysis of these varied characteristics, this research identifies aspects of design that practitioners should prioritize in assessing project carbon emissions. There is a finite amount of time to meet necessary carbon emission reduction goals, and as a result, there is an ever-pressing need to reduce embodied carbon emissions now. The built environment is disproportionately responsible for greenhouse gas emissions, and the ability to reach reduction goals depends on historic and existing building stock. This dependence gives preservation engineers a unique opportunity and responsibility to consider carbon emissions associated with structural interventions.