# The Impact of Internal Insulation on Heat Transport through the Wall: Case Study
## 2 Methodology  
### Subject of Research  
This article focuses on the method of assessing thermal insulation of a wall from the inside. The assessment can be made through two steps as follows:  
1. Before making the insulation: Assessment on the basis of the measurement method of thermal transmittance, Assessment of temperature distribution using the infrared measurement method, Assessment of thermal bridges--FEM modeling (assumptions as for the infrared measurement). 2. After making the insulation: Everything as in point I. The study involved an external wall in an educational building of a University located in the Region of Upper Silesia (Poland). The part of the building above ground level was made as prefabricated reinforced concrete frame structure, namely SF-64, which is consisted of:  
* external reinforced concrete frames \"Z4\",
* internal prefabricated units \"W\",
* ceilings made of hollow core slabs \"S\". The outer longitudinal walls are made of prefabricated reinforced concrete blocks with a corrugated outer surface mounted on transoms. Gable walls, in compliance with the archival design documentation from the 1960s, were made in the form of foam-gas-silicate blocks (Table 1). The facade is frished with ceramic facade tiles of the dimensions of 0.185 m \(\times\) 0.09 m and the thickness of 0.02 to 0.03 m. The texture of the facade in window will strips and attics was concrete and corrugated. On one of the outer walls of the building there are glazed ceramic tiles which are viewed as an element of \"contemporary art\" (Figure 1). Due to the ceramic tiles on the facade, it was impossible to apply thermal insulation on the outer surface of the wall. Therefore, thermal insulation was used on the inner surface of that wall. The entire thermal modernization process consisted in partial thermal insulation of the walls from the outside and the insulation of the gable wall from the inside. For the internal insulation, mineral insulation boards with a thickness of 0.06 m were applied, made of light cellular concrete with a density of 115 kg/m\({}^{3}\). The boards of the dimensions of 0.6 m \(\times\) 0.39 m were installed on adhesive mortar and additionally fixed with mechanical connectors made of PVC plastic. The building after the thermal modernization process is presented in Figure 2a. In Figure 2b, we can see the projection of a fragment of the building with the marked gable wall. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Type of Material** & \multicolumn{2}{c}{**Thermal Conductivity \(\lambda\)**} & \multicolumn{2}{c}{**Thickness d [m]**} & \multicolumn{1}{c}{**Resistance R [m\({}^{2}\)K/W]**} \\ \hline Inner side of the envelope & - & & 0.13 \\ Cement-line plaster & 0.820 & 0.015 & 0.018 \\ Block PCS 800 (wet conditions) & 0.480 & 0.240 & 0.500 \\ Ceramic tiles & 1.050 & 0.030 & 0.029 \\ Outer side of the envelope & & & 0.04 \\  & **Total** & & **0.717** \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Summary of thermal resistance for the gable wall (with mosaic)—the existing state. Figure 1: View of a fragment of the facade with glazed ceramic tiles. Figure 3 presents the classroom in which the wall was insulated. In order to fully illustrate the thermal state of the building, basing on the design represented by the projection in Figure 3, calculations were carried out, as presented in Tables 1-3. Figure 3: Projection and view of the room adjacent to the gable wall. Figure 2: (**a**) Fragment of the building facade insulated partly from the outside and partly from the inside; (**b**) projection of a fragment of the building with the marked gable wall.