Losses are difficult to control because of the lack of characterization method thick materials engineering. The work presented here is an experimental approach to characterize a thick material. We used the power of the sun as a source of excitation of the material. We set up a simple sensor consisting of a Peltier element and a thermocouple for measuring surface. With the help of a chain of acquisition, we recorded in steps of 10 s data flow and temperature in real time on the outside and inside of a building wall. Analysis and appropriate treatments based on the method of quadrupole were then allowed us to estimate the characteristic response time of the wall. Campaign measurement data is done in five days. So we could calculate the characteristic response time of each day, which obviously depends on the weather conditions and the thickness of strained layers in the wall. We determined an average characteristic time of 2h 21 min or 8460 s, which corresponds to a homogeneous material diffusivity (〖a=10〗^(-6) m^2⁄s) at a depth of about 12 cm polled. We believe that the implementation of an infrared camera, it would be possible to make Non-Destructive Testing (NDT) such materials.