A Constructability-Based Dual-Index Framework for Pre-Design Retrofit Feasibility of Legacy Masonry Row Homes

As cities increasingly rely on retrofitting aging housing stock to achieve decarbonization and climate resilience goals, a critical gap remains in assessing whether buildings are viable candidates for retrofit prior to detailed design. This study proposes a constructability-based pre-design screening framework for evaluating retrofit feasibility in legacy masonry row homes using digital inspection data. The framework introduces a dual-index system comprising a Retrofit Feasibility Index (RFI), which quantifies technical readiness across structural integrity, envelope condition, moisture exposure, utilities, durability, and constructability, and an Economic Rehabilitation Index (ERI), which captures relative cost burden across major retrofit drivers. A key innovation of the study is the integration of floor-resolved diagnostics, which reveal significant vertical heterogeneity in retrofit feasibility that is not captured by conventional whole-building assessments. An application to a case study row home demonstrates that upper floors are highly feasible, while ground-level moisture-driven deterioration and structural constraints significantly reduce overall viability, leading to a targeted retrofit classification. The findings further establish moisture as a primary degradation mechanism that influences both structural performance and economic costs. The framework enables rapid, evidence-based retrofit triage under uncertainty, bridging the gap between digital inspection technologies and constructability-driven decision-making in aging urban housing systems.