This paper examines the potential for shielding against electromagnetic (EM) radiation in traditional buildings. The primary objective is to evaluate how effectively these buildings can reduce the intensity of the electric field from external sources, while also identifying the factors that influence this reduction, such as geometry, structure, and the characteristics of EM waves. Measurements were conducted on the transmission parameter S21, which indicates how EM waves propagate through the walls of residential buildings constructed using traditional methods. The buildings analyzed were made from wood, rammed earth, raw bricks blended with straw (known in Croatian as ćerpič), and baked bricks, which served as the reference material. During the measurements, conditions such as the thickness, humidity, and temperature of both the walls and the surrounding environment were carefully controlled. The buildings represented traditional construction styles typical of Croatia and most of Central and Eastern Europe. The results indicate that structures made from rammed earth and raw bricks with added straw significantly decrease the transmission of EM wave energy compared to those made from wood and baked bricks. It is important to note that the walls of wood buildings were considerably thinner than those made from the other materials tested. Additionally, both the moisture content and thickness of the walls contributed significantly to reducing transmission parameters. These findings support the use of these traditional materials for constructing environmentally friendly buildings, while also suggesting the need for further architectural design and testing. Since this research does not cover all types of traditionally constructed buildings—such as stone houses, wicker structures, and dugouts—future studies will aim to expand this investigation to include a broader variety of traditional building styles.