## 2 Materials and Methods
### Materials and Configurations  
The dry-state, thermophysical and basic hydrothermal properties of all the materials simulated for adoption in the building envelope (and as model input parameters) were implemented according to the WUFI material database and previous studies conducted on these materials. Moreover, particular attention was paid to the thermal transmittance temperature-dependent and enthalpy temperature-dependent curve (Phase Change Materials), as these values influence the recorded results to a great extent. The reference wall is a typical external masonry wall. The perimeter walls of the Monastery of Santa Maria de Monfero are irregular and have an average thickness of 100 cm. Two different types of insulation systems were evaluated: thermal plasters (P) and counter walls (C) (Figure 2). The former was used since, in this context, thermal insulating plasters represent an interesting solution, as they are constructive elements that have been used for thousands of years, which show high versatility and increasingly higher technical performances [25]. The latter system was considered because counter walls are by now a common solution for the restoration of old buildings; furthermore, the elements that make up counter walls are often easy to remove. Moreover, these solutions are based on the winning project which has preliminary defined the counter-wall system \"C2 config.\" as a wall retrofit solution (Table 1). Figure 2: Schematic representation of the two considered configurations (not in scale). Both configuration types, i.e., thermal plasters (P) and the counter wall system (C), were designed with a total insulation thickness of 6 cm (assumed from the winning project), with the aim of comparing solutions with reduced thicknesses to be compliant with indoor space constraints. In short, the following were investigated:  
* Different kinds of thermal plasters (P) with aggregates and binders to enhance the thermal properties: Expanded Polystyrene (EPS), natural hydraulic lime, expanded perlite, granulated corncob, granulated cork from bottle caps, Portland cement, microencapsulated Phase Change Materials (PCM) and cellulose flakes. * Counter wall systems (C) considering mineral wool as the insulation layer since it is commonly used. Moreover, other solutions were studied in which the mineral wool was bound with shape-stabilized PCM, Fumed Silica Vacuum Insulation Panels (VIPs) and aerogel blankets. A gypsum wallboard was considered in all \"C\" configurations, in addition to mineral wool. Furthermore, a capillary-active polyurethane foam insulation system was used for comparison purposes. The wall assemblies considered in each simulation are reported in Table 1, while a summary of the material properties is given in Table 2. All configurations were designed with a thickness of \(d\) = 106 cm in order to compare different solutions with the same thickness. A 10 mm thick gypsum board layer was considered for the inner side of the counter wall, while a finishing coat of \(d\) = 3 mm was assumed above the thermal plaster configurations. In addition, the effect of a vapor retarder (\(d\) < 1 mm) was also investigated for the counter wall configurations to investigate whether, in the case of the internal insulation of a historic masonry building, such a membrane could introduce any advantages for the reduction of moisture condensation in the wall layers. The different plasters were studied considering two different finishing coats, that is, a mineral finishing coating that has a high vapor permeability (water vapor diffusion resistance factor \(\mu\) = 4), and a Silicon Resin Finishing with a low vapor permeability (\(\mu\) = 74).