# Structural Analysis of Factors Influencing the Costs of Facade System Implementation
## 4 Results and Discussion
### Identified Cost Factors  
The cost of the construction of elevations of public facilities using facade systems is influenced by many factors. The authors identified cost factors with the analysis of project and cost documentation and as-built settlements for cases, as well as direct interviews with contractors and investors. The factor identification studies presented in this paper constitute an extension of the preliminary studies, the results of which have been previously presented [18]. Finally, the completed study included  
Figure 4: The system of influence-dependence factors within MICMAC (French acronym Matrice d’Impacts Croises Multiplication Appliquee a un Classement, also known as Cross-Impact Matrix Multiplication Applied to Classification) method. Own study based on [29; 30]. Figure 5: Methods and results of the conducted analysis. 80 cases of public buildings constructed in the years 2013-2019 in Poland. The characteristics of the analysed buildings due to their different parameters are presented in Table 1.  
The conducted research identified 15 factors. Fourteen of them were proposed by the authors, while the remaining one, the availability of subcontractors, was proposed by the contractors participating in direct interviews. The factors were then assigned to five groups. The number and type of groups were intuitively proposed by the authors, based on the studies of literature on factors in the construction industry and on experience from engineering practice. The proposed division of factors is illustrated in Figure 6. The factors were additionally given letter symbols to facilitate further analysis. \begin{table}
\begin{tabular}{l l} \hline \hline \multicolumn{2}{c}{**Public Buildings**} \\ \hline Building function & \begin{tabular}{l} Service and commercial \\ Office \\ \end{tabular} \\ \hline Location & \begin{tabular}{l} City centre \\ Outside city centre \\ Out-of-town \\ \end{tabular} \\ \hline Type of facade & \begin{tabular}{l} Aluminium–glass facade \\ Vertilated facade \\ \end{tabular} \\ \hline Type of aluminium–glass facade & \begin{tabular}{l} Million–transom \\ Semistructural \\ Structural \\ \end{tabular} \\ \hline Type of glass & \
\begin{tabular}{l} Fire glass \\ Single glass \\ Insulated glass \\ \end{tabular} \\ \hline Type of ventilated facade cladding &
\begin{tabular}{l} Composite board \\ Aluminium sheet \\ Board fiber cement \\ \end{tabular} \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Characteristics of the analysed buildings. Figure 6: Proposed division of the identified factors. Group 1--materials--contains the following factors: type of aluminium-glass facade, type of glass used, and type of external cladding used for ventilated facades. These are the main parameters directly influencing implementation costs. Group 2--facility characteristics--includes the height of the facility, facade surface, complexity of the building body, and number of window and door frames. The factors of this group describe the characteristics of the building body. Not only does the size of the area have an impact on costs, but its height is also important. High buildings generate additional costs due to the employment of building scaffolding and a crane, the method of transporting facade elements inside the facility, and the need to use specialised equipment dedicated to the assembly of glass panels. Complication of the building body, such as inclined surfaces in combination with straight surfaces, will generate additional costs related to difficult installation. The factor \"the number of window and door frames\" concerns the surfaces of windows and doors (in m\({}^{2}\)) and their condition. High functionality of the windows and doors requires the use of appropriate accessories, such as anti-panic hardware, actuators, automatic sliding door machines, or access control accessories. Group 3 is contractual conditions. These factors have an indirect impact on the cost of the facade.