Design for Maintainability (DFM) of Living Building Envelopes A Prisma-Informed Qualitative Literature Review of Green Façades in High-Humidity Coastal Environments

Abstract

The integration of vegetation into building envelopes through green façades and living walls offers established thermal, environmental, and economic benefits, yet these benefits depend on maintenance performance that is rarely addressed at the design stage, particularly in high-humidity coastal environments where salt-laden air, wind-driven rain, and cyclical wetting accelerate corrosion, biofouling, and substrate degradation. This study adopts a PRISMA-informed qualitative literature review guided by PRISMA 2020 reporting protocols to examine how Design for Maintainability (DfM) principles have been applied to living building envelopes, drawing on evidence identified through Google Scholar and synthesised through thematic analysis. From an initial pool of 2,761 records identified across five search strings, 35 studies met the eligibility criteria and were included in the final synthesis. The findings show that DfM has been most systematically developed within a Singapore-based body of research establishing design-stage maintainability frameworks for vertical greenery systems, but this evidence has not been tested specifically against coastal stressors. Irrigation design emerges as the most consequential and climate-sensitive maintainability variable, with direct effects on vegetation health, biological colonisation, and fire risk, while structural corrosion evidence, though consistent, is drawn largely from general materials-testing literature rather than façade-specific coastal studies. The review concludes that DfM principles for green façades remain underdeveloped for high-humidity coastal contexts specifically, and recommends corrosion-resistant hardware specification, climate-responsive irrigation redundancy, and field-based coastal monitoring as priorities for both practice and future research.