## 2 Materials
### Methods  
Thermal surveys (Thermal Camera FLIR T540 belonging to Texas A&M University was used for the survey. FLIR Tools was used to analyze the thermal images. Since there were no shiny surfaces in the vicinity causing reflections, reflective temperature is not considered for this analysis. Wind conditions are also not considered here as the images discussed are on the interior of the building) at the Residency were conducted by a team of researchers from Texas A&M University and Politecnico di Milano. The surveys were designed with the tropical wet and dry climatic conditions at Hyderabad kept in mind. Surveys were conducted in the month of August and February due to the vast difference of climatic conditions, being the wettest and the driest seasons in the region. While many guidelines and standards exist for the use of infrared thermography, not many elaborate on particular details, and this could be due to the ambiguity of the results presented by the instrument itself. The appearance of the same temperature pattern on a surface that can be due to different causes, depending on both the object of investigation and the boundary conditions of the surrounding environments, are possible reasons that lead to the ambiguity. Knowledge of the building, its history, and construction materials, in combination with a familiarity of the process of thermal imaging and image interpretation, is key to the success of a thermal survey. For instance, in this study, the help of reports from the team of architects working on the building and the expertise of the researchers about IRT was used to good effect. The team also tried to identify a few international standards that, while are not meant for the direct purpose of this survey, would still aid with some of the considerations to be made for the thermal survey. The American Society for Testing and Materials (ASTM) standard C1060 for the Thermographic Inspection of Insulation Installations in Envelope Cavities of Frame Buildings describes that the difference between interior and exterior temperatures of the building should be at least 10 \({}^{\circ}\)C for a 4 h period prior to the survey. The ASTM standard C1153 Standard Practice for Location of Wet Insulation in Roofing Systems Using Infrared Imaging suggests that no appreciable precipitation should occur 24 h prior to the thermal survey [23; 24].  
Emissivity was estimated to be about 0.95 using an insulation tape [14; 25]. The type of day was noted to possibly correlate solar radiation to the results of the survey. With the average sunrise occurring at 6:00 a.m. in Hyderabad, over the course of the survey, the average sunrise time was noted to be 6:00 a.m., and care was taken to capture images at least 6 h after sunrise. This was done in order to allow the building to absorb solar radiation. In the interior, there is no incident sunlight, but this allows increased internal temperatures to be achieved on the inside, relative to the morning, decreasing humidity, and allows the most evaporative flux to take place from wet surfaces. While certain conditions of temperature gradient between the interior and exterior temperatures did not meet the requirements mentioned in the standards, the survey was continued for the purpose of understanding the error in results that suboptimal conditions would produce. The following are the conditions mapped for the two surveys (Table 1).