A Method for ETICS Damage Identification and Early Warning Based on In Situ DIC Monitoring

Early damage detection in External Thermal Insulation Composite Systems (ETICSs) is essential for building safety, yet conventional non-destructive testing methods are often hindered by the wave-absorbing properties of the insulation layer. To overcome this limitation, this study proposes a field monitoring approach based on Digital Image Correlation (DIC) that enables quantitative, multi-point deformation measurement and early warning of ETICS degradation. A 60-day continuous monitoring campaign was conducted on a real building facade under combined environmental loads, during which surface displacements and four environmental variables—temperature, relative humidity, wind speed, and wind direction—were synchronously recorded. By integrating environmental normalization with a dual-criteria anomaly detection rule, the proposed framework separates reversible environmental deformation from irreversible structural damage. A major structural anomaly on 2 October was successfully identified and confirmed by field inspection, demonstrating the system’s early-warning capability. The approach provides a practical, non-invasive solution for ETICS condition assessment without requiring material parameters or destructive testing. Further full-area detection tests on buildings with diverse structural configurations are in progress to strengthen the generalisability of the findings.