In Taiwan, the exterior walls of buildings are often adorned with tiles as the main decorative surface. The typical construction sequence for exterior wall systems includes the structure, base mortar layer, waterproof layer, adhesive layer, and tiles. This study investigates the external interface of the adhesive layer. Strength tests are conducted using the entire groove method and open time. The performance of the construction issues is demonstrated through pull-off strength experiments. The conditions of the adhesive groove and the tile back groove are presented in horizontal and vertical patterns. According to relevant specifications, the adhesive layer’s open time are 10, 20, and 30 minutes. The research objectives can be divided into two points: 1. Verify the tile adhesive layer’s groove pattern and open time through adhesive strength checks. 2. Summarize the temperature and humidity data of exterior wall tile interfaces from construction to the failure stage. The research results reveal patterns in the data obtained from the adhesive layer pull-off tests. The vertical entire groove strength shows a consistent decrease with increasing open time. The highest strength for the vertical entire grooves with an open time of 10 minutes is 3.41 kg/cm2, whereas those for 20 minutes (1.38 kg/cm2) and 30 minutes (1.36 kg/cm2) are close. The humidity of the base mortar is higher on average at an open time of 30 minutes compared to 20 minutes, and the humidity at 20 minutes is equivalent to that at 10 minutes. The higher humidity at an open time of 30 minutes affects the tensile strength of both horizontal and vertical entire grooves, resulting in relatively lower strength data. Most failures at an open time of 30 minutes occur at the interface between adhesive and tile. The research results are expected to provide a reference for construction sites.