Thermal mortar-based insulation solutions for historic walls: An extensive hygrothermal characterization of materials and systems.

• Layered samples of thermal mortars have lower A w than standard prism samples. • The s d of paints can depend on the substrate (singular mortar VS composite sample). • Recommended in technical sheets: s d of complete systems, and also A w for external ones. • Thermal mortars with cork/EPS: lower λ than declared, still of interest in temperate climates. • Thermal mortars: strong dependency of λ on water content. Among thermal insulation solutions for historic walls, thermal renders and plasters appear to be a very feasible option. Thus, this work analyses commercially available thermal mortars suitable for the scope. An extensive experimental campaign showed that testing single materials only, which is the standard requirement for thermal mortar-based systems, is in fact not sufficient for understanding the potential impact of the intervention on walls: whole-systems should also be examined. This study provides a detailedcharacterization of materials and systems, useful as a database for forthcoming investigations on compatibility and efficacy for application on historic walls, via numerical hygrothermal simulations. [ABSTRACT FROM AUTHOR]