Β Introduction
Moisture infiltration can cause significant harm to buildings, leading to structural deterioration and health concerns. Damp proofing is a crucial process that aims to prevent the entry of water or moisture into a structure. By employing various methods, an impermeable layer is created to shield the building. In this blog post, we will explore six widely practiced damp proofing techniques and their effectiveness in ensuring a dry and secure structure.
What is Damp Proofing?
Damp proofing is the process of preventing moisture or water from entering a building or structure through the use of barriers, coatings, or other methods to protect against dampness and potential damage caused by water intrusion.
Methods of Damp Proofing
The following methods are generally practised to prevent dampness in a structure.
- Membrane Damp-proofing
- Guniting
- Surface Treatment
- Integral Damp-proofing
- Cavity Wall Construction
- Pressure Grouting or Cementation
1. Membrane Damp Proofing πποΈ
Membrane damp proofing, also known as a damp proof course (DPC), involves the application of a water-resistant layer between the source of dampness and the vulnerable parts of the structure. This method utilises materials like mastic asphalt, bituminous felt, polymers, plastics, silicone, epoxy, and cement concrete. Depending on the source of dampness, membrane damp proofing can be applied horizontally or vertically on floors, walls, and other surfaces.
2. Guniting π¦πͺ
Guniting, also referred to as shot concrete, is a technique that applies a rich mortar mix (1:3) under high pneumatic pressure using a cement gun. This method is particularly beneficial for retrofitting structures or repairing old concrete works. By spreading or shooting a waterproof layer of mortar over exposed surfaces, guniting makes them water-resistant, sturdy, and resilient. It is commonly used on inferior concrete, masonry walls, pipes, cisterns, and other vulnerable areas.
3.Surface Treatment ποΈπ’
Surface treatment involves applying water-resistant substances or compounds to the structure’s surface to prevent moisture infiltration. Various surfaces are given treatments such as pointing, plastering, and painting. Lime cement plaster (1 cement: 6 lime) is a popular choice for wall treatment. It is mixed with waterproofing admixtures like aluminium hydroxide, sodium or potassium silicates, to enhance its water-repellent properties. Additionally, water-repellent agents such as aluminium or zinc sulphates, sodium or potassium silicates, magnesium sulphate, and barium hydroxide are carefully applied during painting and plastering to ensure comprehensive protection against moisture. For exposed stone and brick surfaces, water repellent solutions can be sprayed to fortify the structure.
4.Integral Damp Proofing π§π§π οΈ
Integral damp proofing involves incorporating waterproofing compounds into the concrete or metal during construction. These compounds, including talc, fly ash, and chalk, fill the pores in the concrete or mortar, reducing its porosity and making it water-resistant. Some waterproof compounds chemically react with the concrete, such as sulfates and calcium chloride, effectively sealing the pores. Other compounds, like oils, fatty acids, soaps, and petroleum compounds such as stearates of calcium, work on the principle of repulsion. When used as an admixture in concrete, they react with it, making it impermeable to water.
5. Cavity Wall Construction
Cavity wall construction is a damp-proofing method that involves creating a gap or cavity between the main wall and an outer wall. This gap acts as a barrier, preventing water and moisture from entering the main wall, thus making the structure waterproof. The minimal or zero contact between the outer and inner walls of the cavity wall reduces the risk of moisture penetration and heat transmission through the wall. In addition to its waterproofing advantages, cavity wall construction offers sound insulation and reduces the occurrence of efflorescence. It is an economical method that promotes hygienic conditions within buildings.
6. Pressure Grouting or Cementation
Pressure grouting, also known as cementation, is widely used in damp proofing to repair and prevent water entry into structures. A fluid mixture of cement mortar (cement, sand, water) is injected into voids, cracks, or fissures in the structure, a process known as grouting. Unlike conventional mortar, this grout mixture has higher fluidity and is specifically designed to fill cracks without spreading. For wider cracks, grout is poured at high pressure to ensure complete filling. Pressure grouting is commonly used in foundation repairs, concrete hardening, and ground consolidation to improve bearing capacity. By effectively sealing voids and cracks, water entry into the structure is prevented.
Conclusionπ―
Damp proofing is essential for maintaining the integrity and longevity of structures. By employing methods like membrane damp proofing, guniting, surface treatment, integral damp proofing, cavity wall construction, and pressure grouting, buildings can be effectively protected against dampness. Each technique offers its own advantages and is suitable for specific situations. Consulting professionals in the field will help determine the most appropriate damp proofing method for your building, ensuring a dry, secure, and comfortable living or working space. Remember, proper damp-proofing not only safeguards your investment but also promotes a healthier environment for its occupants. π§π«π