In building construction, it is very important to reduce energy consumption and provide thermal comfort. In this regard, defects in insulating panels can compromise the capability of these panels of reducing the heat flow by conduction with the surroundings. In recent years, both experimental techniques and numerical methods have been used for investigating the effect of defects on the thermal behavior of building panels. The main novelty of this work regards the application of both numerical and experimental approaches based on infrared thermography techniques for studying the effects of defects such as debonding on the insulation properties of cork panels. In particular, the effects of defects were investigated by using the Long Pulse Thermography technique and then by analyzing the thermal behavior of the panel during the cooling phase. Results show the capability of the proposed approaches in describing the effects of defects in cork panels such as detachments and the benefit effect of a shield coating in improving the insulation properties of the panel.