In general, all structures built below the earth's surface and whose water table is close to the earth's surface are protected by waterproofing. Bituminous membranes and sealing compounds are typically used as foundation waterproofing.
The structural element subjected to tensile stresses may crack due to loading and, as a consequence, the reinforcement may corrode if it is in a corrosive environment.
For this reason, structural elements such as concrete walls, pile tops, slabs and beams are normally protected by sealing.
However, concrete piles built underground and projecting into the rock are not waterproof because they are subject to axial compressive stresses. Even at the level of the top plate of the pile, it is very rare for tensile stresses to form in the piles.
Different types of waterproofing are discussed in the article Concrete waterproofing and can be used for more information on choosing the type of sealing.
Membrane waterproofing is commonly used to protect underground structures.
The bituminous slabs are placed on the screed before concreting and the screed is placed on top of the waterproofing work. Once the subsurface is concreted, the side surfaces are sealed.
In modern construction, the use of crystalline waterproofing is becoming increasingly popular due to its low construction cost and ease of use.
