## 4 Findings
### Standard and Marine Service Conditions  
This stage of the empirical research was based on comprehensive fieldwork on stone cladding deterioration over time. The exterior claddings of 87 tall and high-rise (more than 4 floors) buildings were sampled by visual observations at all heights from the ground level and the roof level, as well as by analysis of 10-12 photos. The claddings were graded according to a pre-tested template [30] (see Appendix A). Degradation sources, such as marine environment, air-polluted environment, poor details (e.g., lack of joints and expansion joints, poor fixing details, and poor materials), were rigorously considered. The data gathering referred to factors such as the wind direction, the orientation of the large facade towards the wind direction, and the size of the natural stone panels. Observations with an evident failure degradation mechanism were excluded from the survey. The sample was further categorized according to the fixing method of the stone and the exterior service conditions. Tables 4 and 5 delineate examples of various physical and visual degradation levels in three wet- and dry-fixed stone claddings taken from the sample inspected. Three different scatter diagrams were prepared from the results, where standard conditions reflect the normal conditions for which the building was designed, constructed, and maintained, and a marine environment reflects harsh environmental conditions: (1) dry-fixing exterior stone cladding under standard service conditions, (2) dry-fixing exterior stone cladding exposed to marine environment service conditions, and (3) wet fixing exposed to a marine environment. The buildings in the sample exposed to marine conditions were located in close proximity to the seashore (less than 400 m) on the central coast-line trip of Israel, considering the exposure to local sea water breeze regime conditions. This region is characterized by a mild rain regime (annual rain fall of 400-700 mm), 30-60 annual rain days, and a light wind regime (mainly south-west). The orientation of the large facade was found to be west in the majority of the sample, exposing the facade to the effects of the  
Figure 4: Relationship between the critical content of sodium sulfate and capillary water absorption of limestones. south-west wind regime. The dry-fixed stone cladding sample was limited to claddings aged up to 35 years, as this cladding is a relatively new method for exterior finishing in Israel and has only been implemented on a large scale since approximately 1985. The performance grading indicated that as a result of all facades, in a marine environment where the wind regime is dominantly a west wind, deterioration appears mainly in western facades (facing the seashore). Observations were taken at all height levels by observations at a roof level and a ground level, and by analysis of 10-12 photos. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Samples** & **Service Conditions** & **Type of Cladding Technique** & **Age [years]** & **Physical/Visual Grade 1** \\ \hline \hline  & Marine & Wet-fixing & 15 & 5; 4 \\  & environment & Wet-fixing & 28 & 3; 4 \\  & Marine & Wet-fixing & 40 & 3; 3 \\  & environment & Wet-fixing & 40 & 3; 3 \\ \hline \end{tabular} \({}^{1}\) According to Tables 1 and 2 and Equation (1).  
\end{table} 
Table 4: Characteristics of three wet-fixed stone claddings observed in marine environment. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Samples** & **Service Conditions** & **Type of Cladding Technique** & **Age [years]** & **Physical/Visual Grade 2** \\ \hline \hline  & Marine environment & Dry-fixing & 17 & 5; 4 \\  & Marine environment & Dry-fixing & 21 & 4; 4 \\  & Marine environment & Dry-fixing & 40 & 3; 3 \\ \hline \end{tabular} \({}^{2}\) According to Tables 1 and 2 and Equation (1).  
\end{table} 
Table 5: Characteristics of three dry-fixed stone claddings observed in marine environment.