Vernacular architecture is an important part of cultural landscapes. The use of traditional sandstone roofing for rural constructions has declined significantly in the Aragonese Pyrenees (Spain), leading to important changes in the cultural landscape of this UNESCO World Heritage site. Factors leading to the decline are studied, including laboratory analyses/tests to evaluate the material's shortcomings, as well as local visits and a bibliographic search to examine technical, building regulatory, and administrative issues. Clay accumulation along the sandstone's bedding planes was the main material-related cause of deterioration. However, a shortage of suitable replacement material as well as technical problems related to the adaptation to modern building codes were also identified as important factors contributing to the decline. Solutions for their remediation are discussed and selection criteria for the identification of suitable replacement material are proposed. The described methodology is applicable to the study of endangered vernacular architecture worldwide and will help raise public awareness and institutional support.

乡土建筑是文化景观的重要组成部分。在阿拉贡比利牛斯山脉（西班牙），用于农村建筑的传统砂岩屋顶的使用已大大减少，这导致了联合国教科文组织世界遗产的文化景观发生了重大变化。研究了导致下降的因素，包括用于评估材料缺点的实验室分析/测试，以及本地访问和书目搜索，以检查技术，建筑法规和行政问题。沿砂岩层理平面的粘土堆积是与材料有关的主要退化原因。但是，也发现缺少合适的替代材料以及与适应现代建筑规范有关的技术问题也是造成这种下降的重要因素。讨论了解决方案，并提出了确定合适替代材料的选择标准。所描述的方法学适用于全球濒危本土建筑的研究，将有助于提高公众意识和机构支持。