What are the general methods for exterior wall inspections?

1. Knock Test Method The knock test method is a method of judgment based on experience. Generally, a small hammer is used as a detection tool to identify the density and internal hollows of an object by listening to the frequency and sound of the knocking sound. This method is simple with fewer procedures, but it is greatly influenced by subjective factors and relies heavily on the experiential judgment of the inspector, which results in high labor intensity and low efficiency.

2. Visual Inspection Method The visual inspection method is a method of judgment based on experience, generally determining the condition of the structure based on personal visual observations. This method has few procedures and requires less human and material resources. However, it primarily relies on individual experience and is greatly influenced by personal subjective factors. Since the source of hollowing and leakage may not be found, even with high professional skills of the inspectors, it may not be possible to make a judgment.

3. Infrared thermal imaging detection utilizes an infrared thermal imager to explore the infrared radiation energy of various parts of an object. It directly displays the detection skill of discontinuities and defects on materials, structures, and their interfaces through the thermal image formed by the distribution of the object's surface temperature field. It identifies hollowed-out and leaking areas without the need for scaffolding, prevents risky operations, and can quickly and non-intrusively scan large areas for construction surface defects and leakage conditions.