Some clays have the ability to increase in volume when absorbing water, inducing swelling pressure and swelling strain. This type of clay is an unsaturated soil named expansive soil. Expansive soils are located in new desert cities in Egypt. The development of such arid areas for urban expansion driven by the increase in population and economic progress faces a challenge due to significant damage to buildings and infrastructures such as highways pipelines found over such problematic soil that causes economic losses. Numerous factors contribute to the problem, such as soil type, soil properties, foundation type, and nature of the project. The physical and chemical properties of such clays affect quantitatively its swelling potential. The most important properties are initial moisture content, initial dry density, clay fabric, compaction method, compaction energy, clay mineralogy, stress path, surcharge pressure, degree of saturation and sample thickness. This paper aims to deeply understand the mechanism of swelling and factors influencing its potential to help the geotechnical engineer select a suitable treatment measurement to alter its detrimental effects by modifying the influencing factors, consequently making aired areas more feasible for construction purposes.