Environmental Performance of a Lightweight Double-Layer Covering for In Situ Archaeological Site Protection: The 1st C. CE Roman Tomb of the Two Families (Carmona, Spain)

<jats:p>The preventive conservation of ground-level archaeological sites requires not only protection from direct weathering but also effective control of the surrounding micro-climate. Conventional archaeological coverings generally fail to provide adequate environmental stability while generating significant physical, visual, and environmental impacts. This study presents an integrated methodology for the design, optimization, and validation of a lightweight double-layer covering conceived as a climate-responsive environmental system rather than a passive protective shelter. The proposed workflow integrates parametric optimization of geometry and materiality, Life Cycle Assessment (LCA), environmental monitoring, Computational Fluid Dynamics (CFD) simulations, and experimental validation. The methodology was applied to the 1st c. CE Roman Tomb of the Two Families, located within the Carmona Archaeological Complex (Spain), where the environmental performance of the covering was evaluated through more than one year of in situ monitoring and numerical simulations. The results demonstrate that the proposed solution effectively moderates the site's microclimate while significantly reducing environmental impacts and material consumption compared with conventional protective structures. The close agreement between monitored and simulated data validates the proposed design methodology and confirms the reliability of the environmental models. This research demonstrates that lightweight archaeological coverings can be conceived as climate-responsive environmental infrastructures, providing a transferable methodological framework for preventive conservation that integrates structural efficiency, environmental control and sustainability from the earliest stages of the design process.</jats:p>