Vernacular Bioclimatic Design and Conservation Challenges of Ksar Zgag El-Hadjadj: A Multi-Scalar Documentation of Saharan Earthen Heritage

Saharan ksour hold centuries of empirical bioclimatic knowledge, yet detailed documentation of their design principles remains scarce, particularly for non-UNESCO settlements. This research presents a multi-scalar documentation of Ksar Zgag El-Hadjadj, a fortified earthen settlement in Laghouat, Algeria. Field investigation across seasonal thermal extremes combined on-site measurement, photographic recording, and structured interviews with elderly residents retaining traditional building knowledge, analyzed for correspondence with established passive-design frameworks. The study reveals an integrated environmental system operating across scales: compact urban morphology providing solar shading and wind reduction, a hierarchical street network modulating microclimate, and an introverted courtyard typology combining thermal mass, ventilation, and adaptive occupation. Critically, this performance is inseparable from the social practices sustaining it—communal maintenance and seasonal-daily spatial use. Advanced deterioration follows directly from the breakdown of these practices, while cement interventions specifically degrade bioclimatic function. The study reframes vernacular heritage preservation as a socio-technical challenge.