Conference Agenda

Architectural responses to climate change often focus on new construction, minimizing non-renewable resources consumed by buildings and/or reducing operational and embodied carbon. However, considering that the building stock is predominantly existing (the New Buildings Institute estimates new construction affects only two percent of building stock annually), incrementally improving performance code mandates for new buildings is not an expedient way of reducing energy consumption and carbon emissions within the larger building stock (DiNola, 2022).

Wider discourse examines whether the appropriate architectural response should be repair or replacement, including the range of interventions within this prospect: from restoration and preservation, recovery, retrofit, reuse, remediation, to new construction. Reliance on cost-benefit analysis ignores myriad contextual considerations informing the design process. While new construction is predictable in its replicability and scalability, repair requires a more nuanced approach and a sensitive assessment of broader existing conditions.

How then, can designers offer responsible guidance when the answer is, “It depends”? Physical characteristics define the parameters of a project, including the age of a building and type of construction. Beyond these, the carbon footprint can be determined, with the risk profile relative to climate change and natural hazards overlaid. Criteria establishing value can be static and tangible. More challenging are the dynamic and intangible criteria: cultural or historical significance, community or kinships, or social equity. In addition, societal considerations weigh preservation in opposition to erasure, acceptability versus suitability, standardization against the mark of handicraft.

This paper will catalog a range of complex factors mitigated in decision-making along the repair–replacement spectrum and a framework for evaluating them, cohesively examining three distinct case studies: repair of a culturally and historically significant landmark, retrofit of multi-family housing through overclad systems, and replacement of low-income housing. The authors identify both universal and specific considerations that architects face when evaluating building-performance-driven solutions.

This paper discusses the energy-efficiency retrofit of an existing multifamily residential complex in Murray, Utah. Funded by the Department of Energy (DOE), the project included two buildings, each comprised of four residential units. The retrofit primarily focused on improvements to the building enclosure and building systems of each unit. The overall goal was to investigate how modular design/construction and automation can be used in energy-efficient retrofit projects, from data capture of existing conditions, modeling, and documentation development to prefabrication of modular facade assemblies and building systems components for heating and cooling. To assess the building's current conditions and identify suitable retrofit strategies, the project team conducted a thorough analysis, incorporating archival data, empirical evidence, and computational modeling. Given the buildings’ age (constructed in the early 1960’s) and limited records, a comprehensive 3D BIM was developed by laser scanning the existing structures and finalizing the model based on in-situ observations and measurements. The model was used for various design studies throughout the retrofit process, including building enclosure design, coordination between architectural and mechanical retrofit strategies, as well as documentation and collaboration. The retrofit project encompassed various energy efficiency measures, including recladding with modular, prefabricated insulated facade components, window replacement, and air sealing. Improvements to building systems were implemented, including new heating and cooling systems, as well as the domestic hot water system. Actual energy consumption data was collected, and energy modeling was conducted to investigate the impacts of energy-, carbon-, and energy-cost-savings of retrofit strategies. The paper captures the characteristics of the multi-family complex (existing conditions), retrofit process (from design to construction), and discusses research that was conducted to evaluate specific retrofit design strategies (building enclosure and building systems) and their impacts on energy performance. It concludes with recommendations on how multi-family residential energy-efficiency retrofit projects can be executed.

as one of the largest contributors to greenhouse gas emissions, the construction industry faces increasing pressure to adopt more sustainable practices. In this context, Modular Construction (MC) has emerged as a promising sustainable process of industrializing construction activities, where different tasks can be transferred into off-site facilities and automated, regulated, and controlled within a specific environment. The potential benefits of MC extend beyond improved productivity, quality, and cost efficiency, encompassing waste and environmental footprint reduction. This study aims to provide a survey of literature regarding MC techniques and their effects on mitigating buildings' environmental impacts. Using the PRISMA method and relevant keywords in research databases, 30 articles were selected and analyzed. The analysis focused on identifying trends, methodologies, and outcomes reported in recent research on the environmental performance of MC. The results show that Life Cycle Assessment (LCA) is commonly employed to evaluate MC's carbon emissions and energy consumption, allowing for a comprehensive evaluation of environmental impacts across various stages of a building's life cycle, from material production to end-of-life scenarios. However, the application of LCA varies significantly across the literature in terms of tools utilized, scopes defined, and datasets employed, among other factors. The findings of this research indicate mixed results regarding the environmental performance of MC. Results reveal that while MC often demonstrates lower environmental impacts than conventional construction, outcomes are inconsistent due to variability in LCA methodologies, material choices, transportation logistics, and project-specific conditions. Key practical implications include the need for standardized LCA frameworks to enable reliable comparisons and the importance of context-specific strategies to maximize MC's sustainability benefits. These outcomes underscore the potential of MC to advance climate goals but emphasize that its environmental efficacy depends on systematic implementation and further innovation in assessment practices across diverse contexts and building types.