# Retrofitting a Building's Envelope: Sustainability Performance of ETICS with ICB or EPS
## 5 Results
### Comparative 3E Performance of ETICS with ICB and Expanded Polystyrene (EPS)
#### 5.2.1 Comparison of the Carbon and Energy Consumption Balances of ETICS with ICB or EPS Boards  
The importance of the use of local renewable resources in buildings for energy renovation is highlighted by this study, namely the application of ETICS with ICB as external rendering and insulation of external walls as an alternative to the application of the same system with a non-renewable material as insulating material (EPS). This section presents the results achieved in terms of the comparison of the environmental and energy consumption balances related to the application of the 3E-C2C method to the use of these construction systems in 12 of the 14 external alternatives defined for this study.  
The results achieved in the comparison of the C2C carbon footprint of the external wall alternatives, expressed by the GWP (Figure 7), demonstrated an environmental advantage of the alternatives with ETICS with ICB at stages A1-A3 between 29% and 54% (without energy for heating or cooling) when compared to solutions with similar thickness using EPS. In fact, this difference is proportional to the thickness of the insulation board applied on the external surface. This environmental disadvantage results from the use of nonrenewable resources in the production of EPS. The GWP on the B2-B4 stages are similar for all alternatives, due to their equal maintenance strategy (Table 2) and represents  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Wall Type**} & \multirow{2}{*}{**Insulation Material**} & \multirow{2}{*}{**Designation**} & \multicolumn{2}{c}{**Thickness (m)**} & \multicolumn{1}{c}{**U-Value**} \\ \cline{3-6}  & & & **Insulation** & **Wall** & **(W/(m\({}^{2,\circ}\)C))** \\ \hline \multirow{8}{*}{Single-leaf} & None & W1 & - & 0.26 & 1.36 \\  & ICB & W4 & 0.06 & 0.32 & 0.45 \\  & EPS & WE4 & 0.06 & 0.32 & 0.42 \\  & ICB & W6 & 0.08 & 0.34 & 0.37 \\  & EPS & WE6 & 0.08 & 0.34 & 0.34 \\  & ICB & W7 & 0.09 & 0.35 & 0.34 \\  & EPS & WE7 & 0.09 & 0.35 & 0.31 \\ \hline \multirow{8}{*}{Cavity wall} & None & W8 & - & 0.35 & 0.95 \\  & ICB & W11 & 0.06 & 0.41 & 0.39 \\ \cline{1-1}  & EPS & WE11 & 0.06 & 0.41 & 0.37 \\ \cline{1-1}  & ICB & W13 & 0.08 & 0.43 & 0.33 \\ \cline{1-1}  & EPS & WE13 & 0.08 & 0.43 & 0.31 \\ \cline{1-1}  & ICB & W14 & 0.09 & 0.44 & 0.30 \\ \cline{1-1}  & EPS & WE14 & 0.09 & 0.44 & 0.28 \\ \hline \hline \end{tabular}
\end{table}
Table 5: Designation, thickness and type of insulation board in the ETICS applied, and thermal performance (U-value) of the wall after rehabilitation.  
between 23% and 39% of their C2C GWP, without considering the energy consumption for heating and cooling.  
The C2C consumption of PE-NRe (Figure 8) expresses a performance similar to GWP. In fact, the environmental advantages of the ETICS with ICB insulation at stages A1-A3 in comparison to EPS solution is also proportional to the thickness of the insulation board applied and can vary from 44% to 78%, thus confirming the environmental advantage of using renewable materials in the production of the insulating element.