## 2 Materials and Methods  
### Materials, Dosages, and Samples Elaborated  
This study was conducted using the elements shown in Figure 1 and are described as follows:  
* E-35 Plaster: Supplied by Placo-Saint Gobain (Madrid, Spain). This binder has a pureness index of >90% and particle size of \(\mathcal{O}\)0-0.2 mm and main characteristics are shown in Table 1. Thermal conductivity value is set between 250 and 300 mW/m\(\cdot\)K. This product meets the standard 13279-2:2014 [36] requirements. The material's main composition, set using X-ray fluorescence analysis, is as follows: CaSO\({}_{4}\) (99.7%), Al (0.022%), Fe (0.035%), Si (0.068%), Sr (0.157%), and P (0.01%).  
* Water: Canal de Isabel II water was used in this study. The Canal de Isabel II is the public company responsible for the management of the integral water cycle in the Community of Madrid. The main properties of this water include an average hardness (25 mg CaCO\({}_{3}\)/L); pH between 7 and 8.5; and chloride content between 1 and 1.5 mg/L. It also contains other compounds, such as nitrate (0.6 mg/L), nitrite (<0.05 mg/L), sulphate (5.3 mg/L), calcium (17.8 mg/L), Fe\({}_{2}\)O\({}_{3}\) (0.01 mg/L), and copper (<0.005 mg/L) [37].
* Perlite (P): Supplied by Semillas Batlle S.A., (Barcelona, Spain). The expanded perlite is a glassy volcanic rock mainly composed of SiO\({}_{2}\), Al\({}_{2}\)O\({}_{3}\), Fe\({}_{2}\)O\({}_{3}\), TiO\({}_{2}\), CaO, MgO,  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Fire Resistance** & **Thermal Conductivity** & **pH** & **Granulometry** & **Water Vapor Diffusion** & **Flexural Strength** & **Purity Index** \\ \hline \multirow{2}{*}{Euro class AY} & 250–300 & \multirow{2}{*}{\(>\)6} & \multirow{2}{*}{0–0.2 mm} & \multirow{2}{*}{\(\mu\) = 6} & \multirow{2}{*}{\(>\)3.5 N/mm\({}^{2}\)} & \multirow{2}{*}{\(>\)92\%} \\  & mW/m\(\cdot\)K & & & & \\ \hline \hline \end{tabular}
\end{table}
Table 1: E-35 Iberoola main properties.  
Figure 1: Materials used in this study. (**a**): E-35 Plaster; (**b**) Recycled Glass Wool; (**c**) Expanded Perlite.  
Na\({}_{2}\)O, and K\({}_{2}\)O. Particle size is >\(\O2\) mm. This material has no reaction when mixed with plaster and has an impressive performance, both physical and mechanical [38].
* Recycled glass wool (RGW): Provided by URSA, S.A. (Madrid, Spain) [39]. The glass wool is mainly composed of sand, soda ash, dolomite, limestone, olexite, and anhydrite, and it is a widely used for insulation in buildings. This material comes from construction and demolition waste, thus this application extends its useful life. Its regular thickness is around 30-50 mm but for this study, the glass wool was manually divided into 5-10 mm thick layers.
* The samples are named as follows: E-00-A-LL, where E is for E-35 plaster used, 00 is for water/ plaster ratio, A is for aggregate, depending on whether it contains perlite, and LL corresponds to the number of RGW layers and its position. This can be 1L for one layer, 2L for two layers, and 1 LU for a sample with the layer on top. Table 2 shows dosages and amounts of material used along with their configurations.  
* To conduct this study, different-sized samples were established within the context of the tests performed. Samples were elaborated according to the EN 13279-2:2014 Standard [40]. The tests performed and samples used in each test are shown in Table 3.