Traditional roofing with sandstone slabs: Implications for the safeguarding of vernacular architecture

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.