An Embodied Carbon Life Cycle Assessment (LCA) for Earthen and Bio-Based Finishing Systems in Residential Interior

This study examines how interior material finish characteristics—specifically Embodied Carbon (EC) and moisture permeability—affect the total environmental performance of earthen residential interiors, focusing on the Indian context. Initial observations revealed a recurrent disconnect where low-carbon earthen structures (Rammed Earth, CSEB) were frequently finished with high-EC, synthetic materials (e.g., vitrified tiles, acrylic distempers). The research problem is the lack of empirical evaluation and quantitative, design-oriented metrics linking interior finish properties to total Life Cycle Carbon (LCC) and breathability performance. A quantitative survey indicated that, despite an awareness of EC, designers are primarily deterred from using low-carbon, bio-based alternatives (like clay or lime plasters) by performance anxieties, namely concerns over long-term durability and maintenance requirements (68.4% concern). The study posits that bio-based and breathable finishes reduce the total embodied carbon of the interior system and improve the functional performance (hygrothermal stability and wall health) of earthen construction. All hypotheses are designed to be testable using LCA databases for kg CO2e and scientific metrics like the vapor diffusion resistance factor (mu) and Moisture Buffering Values (MBV). The final objective is to propose a "Regenerative Interior Specification Guide" supported by measurable data to bridge the specification gap driven by risk aversion.