A New Decision-Making Tool for Guiding the Sustainability of Adaptive Reuse of Earthen Heritage Complexes in Desert Oases

Earthen heritage in desert oases reflects local identity, craftsmanship and traditional knowledge but is facing increasing threat of disappearance from material vulnerabilities, social abandonment and unsuitable interventions. This study develops and validates a novel decision-making tool to guide stakeholders in selecting the most suitable building technology for the adaptive reuse of earthen heritage complexes to ensure their long-term sustainability while maintaining their cultural and social values. The proposed methodology combines the Integrated Value Model for Sustainability Assessment (MIVES) and Delphi technique to evaluate the cultural, economic, environmental and social aspects. Quantitative and qualitative indicators were defined through literature review and weighted by experts in two rounds of Delphi to obtain comparable sustainability index for each building technology. The evaluation of economic and environmental aspects was based on literature data, while cultural and social aspects were assessed through a third round of Delphi with local participants. The tool was applied to the Adrere Amellal Ecolodge in Siwa Oasis, Egypt, comparing three building technologies: Karshif traditional earthen technique, commonly used red bricks and innovative 3D-printed saltblocks. Karshif achieved the highest sustainability index (0.77) due to its cultural values, social acceptance and environmental performance. The findings demonstrate the potential of traditional earthen techniques to ensure sustainable adaptive reuse, providing a replicable method for sustainable adaptive reuse of earthen heritage in desert oases in Egypt and worldwide.