One of the most frequent sources of moisture and the most difficult to treat is the rising humidity from undrained soils, commonly referred to as rising damp. Rising damp occurs by capillary suction, osmotic pressure, or electro-osmosis. The water rises through the porous building materials and progresses until there is a balance between absorption (i.e., the quantity of water that enters the porous material) and evaporation (i.e., the amount of water that leaves the porous material) of water. This phenomenon is governed by several factors key of which include: the amount of water in contact with the building element, the conditions of the surface evaporation; porosity of the walling material; thickness of the walling material; orientation of the wall; as well as the presence of salts.

Currently, the solutions used to overcome the rising damp problem in both new and existing buildings consist of creating a physical barrier that limits the progression of the water in the walls, coating the walls with waterproof products, waterproofing the basement of buildings, or installation of drains. Alternative solutions like resin injections, installing electric polarization devices, and the likes have also appeared on the market. However, these operations are often complex and costly and are not guaranteed to provide a long-term solution. The surest way to deal with this problem is to control it at the source.

This implies that several factors must be considered during the construction of the foundations to block the underground water from rising. The building performance laboratory of the Department of Construction Technology and Management, in collaboration with industry, has come up with an eco-friendly block walling material that has the potential to control the problem of rising damp in new buildings.