Physical characteristics of typical Lebanese soil for green roofs

Given that water is a vital and scarce global resource, and considering the escalating climate change crisis, it is imperative to investigate soil water retention capacities and thermal behavior, which can be used in sustainable urban solutions. In particular, green roof systems offer promising strategies for mitigating urban heat island effects, road flooding, and stormwater management. This study investigates the thermal and hydrological behavior of typical Lebanese brown and gray soils under controlled laboratory conditions to evaluate their suitability as substrates for green roof applications. Soil samples were standardized, saturated, and monitored for bulk density, temperature dynamics, and volumetric water content using calibrated sensors and automated data recording systems. The results indicate that brown soil exhibits superior thermal inertia, maintaining more stable temperatures, while grey soil demonstrates enhanced water retention capacity. These findings highlight the balance between thermoregulation and moisture retention in substrate selection, providing valuable insights for optimizing the performance of green roofs in Mediterranean climates.