Carbon Reduction Through 4Rs: Adaptive Reuse of an Existing Building(s) on Site

Abstract

This research proposes a module to assess carbon reduction through the 4Rs (Reduce, Reuse, Recycle, Recover) within the framework of adaptive reuse of existing buildings. The study proposes retrofit as a potential solution in response to increasing demolition practices and resource-intensive construction, to reduce material consumption, embodied emissions, and construction waste, while retaining architectural identity and continuity.

The methodology is based on on-site documentation, material inventory mapping, and condition assessment to quantify existing material systems. Two scenarios are considered: a baseline case that considers the building as it is, and a proposed case that utilizes the 4R framework by selective retention, repair, reuse, and replacement of materials. Embodied carbon is calculated using a spreadsheet-based carbon assessment tool from Solar Decathlon India (SDI), supported by standard emission factor datasets and material quantification.

The baseline scenario results in 19.4 tonnes CO₂e, while the proposed retrofit reduces emissions to 3.8 tonnes CO₂e, achieving a reduction of 15.6 tonnes CO₂e, equivalent to an 80.4% decrease in embodied carbon. The findings highlight the importance of material-level decision-making, particularly structural retention and debris reuse, in minimizing new material demand and associated environmental impacts.

The study establishes a quantifiable and replicable framework that integrates material evaluation, carbon quantification, and circular strategies, offering potential for application in similar retrofit contexts and informing future low-carbon architectural practice.