## 3 Results and Discussion
### Methodology for Relative Assessment of Sustainability of Construction Solutions (MARS-SC)  
Concerning the MARS-SC, the same external wall base was selected for all solutions: a double ceramic hollow brick wall with a 10 mm cement brick laying mortar and 15 mm cement plaster mortar, finished with three coats of water-based plastic paint on both sides. Within this structure, eight different types of insulation, from commonly used materials to unconventional bio-based materials, were chosen for evaluation. Table 2 summarises the data for the density and thermal conductivity of materials, along with the necessary thickness to achieve a thermal resistance of 3 (m\({}^{2}\) K)/W for insulation materials and the mass per square meter of each material, tailored to suit the requirements of the MARS-SC tool. Table 3 presents the required mass per square meter of materials for the external wall base. After quantifying all materials outlined in the proposed solutions, environmental impact data were obtained from the LCA database and specific EPDs. Table 4 summarises the impacts per kilogram of material. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Material** & **Density (kg/m\({}^{3}\))** & **kg/m\({}^{2}\)** \\ \hline Ceramic hollow brick (30 \(\times\) 20 \(\times\) 15 cm) & 625 kg/m\({}^{3}\) or 5.2 kg/um (15.36 \(\times\) \(\text{m}^{2}\)) & 159.74 \\ Cement plaster mortar—15 mm & 1900 & 57 \\ Cement brick laying mortar—10 mm & 1900 & 44.65 \\ Water-based plastic paint—3 coats & 1.56 kg/L & 0.75 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: External wall base materials quantity required. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Constructive Solution** & **Material Description** & **Material Carbon Intensity** \\  & **Material Description** & **(MCI) (kg CO\({}_{2}\)e/m\({}^{2}\))** \\ \hline Concrete masonry unit with insulation & Permacon concrete masonry of 20 cm and XPS foam board & 235 \\ Concrete masonry unit with insulation & Permacon concrete masonry of 20 cm and wood fibre board & 107 \\ Compressed earth blocks with insulation & Compressed earth block wall with XPS foam board & 76 \\ Compressed earth blocks with insulation & Compressed earth block wall with STEKO wood fibre batt & \(-\)52 \\ Compressed earth blocks with insulation & Compressed earth block wall with cast in situ hemprete & \(-\)138 \\ Structural insulated panel & EcoCocon straw panel & \(-\)200 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: The material’s carbon intensity according to the constructive solution based on BEAM results. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Material** & **Density (kg/m\({}^{3}\))** & **Thermal Conductivity (W/(mK))** & **Thermal Resistance (m\({}^{2}\) K)/W** & **Thickness (m)** & **kg/m\({}^{2}\)** \\ \hline Conventional material—XPS & 25.95 & 0.033 & 3.00 & 0.10 & 2.595 \\ Conventional material—EPS & 18.50 & 0.030 & 3.00 & 0.09 & 1.665 \\ Conventional material—Rock wool & 95 & 0.037 & 3.00 & 0.11 & 10.545 \\ Conventional material—Glass wool & 16 & 0.037 & 3.00 & 0.11 & 1.776 \\ Bio-based material—Corkboard & 110 & 0.039 & 3.00 & 0.12 & 13.455 \\ Bio-based material—Hep and flax & 37 & 0.040 & 3.00 & 0.12 & 4.320 \\ board & 35 & 0.040 & 3.00 & 0.12 & 4.200 \\ Bio-based material—Hepp fibre & 100 & 0.052 & 3.00 & 0.16 & 15.600 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: The technical information and quantity required for insulation material.