General principles of damp proofing:
On both wet proofing processes, the basic concepts to be followed are as follows:
- Horizontal or vertical may be the damp proofing course.
- The full thickness of the wall should protect the horizontal damp proofing path.
- The horizontal damp proofing course should be continuously laid at the junction and corners of a wall.
- The mortar bed should be even and is prepared to obtain the flat damp-proofing time.
- The damp proofing course should be laid to make continuous protection.
- The damp-proofing course should not be exposed to the wall surface; otherwise, it is likely to be damaged by carpenters, tile layers, etc.
- It is adversely impacted by dampness due to flooding in the house. To stop water in a system, the following procedures are usually followed.
Membrane damp proofing
This consists of providing a layer or membrane of water repellent material between the source of dampness and the part of the structure adjacent to it. This type of coating is commonly known as the Damp Proofing Course. It may comprise bituminous felts, mastic asphalt, silicone, epoxy, polymers, plastic, polythene sheets, cement concrete, etc. DPC may be given horizontally or vertically on walls and floors, depending on the cause of dampness. This waterproofing method is mostly done by a waterproofing company in Mumbai.
Integral damp proofing
This consists of adding certain waterproofing compounds with the concrete mix to increase its impermeability. Such compounds are available on the market in powdered as well as liquid form. The compounds made from clay, sand, or lime (chalk, talc, fuller’s earth, etc.) help fill the voids in concrete and make it waterproof.
Another form of a compound like alkaline silicates, aluminium sulfates, calcium chloride, etc., reacts chemically when mixed in concrete to produce waterproof concrete. Many commercially made preparation of waterproofing compounds is commonly used. The number of waterproofing compounds to be added to cement depends upon the manufacturer’s recommendations.
As described earlier, the moisture finds its way through the pores of the material used in finishing. To check the entry of the water into the pores, they must be filled up. Surface treatment consists of filling up the pores of the surface subjected to dampness. The use of water repellents metallic soaps such as calcium and aluminium oleates and stearates effectively protects the building against heavy rain ravages. The bituminous solution, cement coating, transparent coating, paints, and varnishes fall under this category. In addition to other treatments provided to walls, lime cement plaster is the one widely used. The walls plastered with cement, lime, and sand mixed in the proportion of 1:1:6 is found to serve the purpose of preventing dampness in a wall due to rain virtually.
This consists of depositing a waterproof layer of rich cement mortar over the surface to be waterproofed. The operation is carried out by use of a machine known as a cement gun. In general, the assembly consists of a device with a mixing materials arrangement and a compressor for forcing the mixture under pressure through a flexible hosepipe of 50 mm dia. The hosepipe has a nozzle at the free end, of which a separate connection under load supplies water. The surface to be handled is carefully washed and correctly wetted with soil, dust, grease, or lack of particles. Cement and sand are then pumped into the system, usually taken as a proportion of 1:3 to 1:4. By keeping the cement gun’s nozzle at a distance of 75 to 90 cm from the working forehead, this mixture is finally shot on the prepared surface under a pressure of 2 to 3 kg/sq.cm.The water supply in this mix can be controlled by regulating the water supply hose attachment valve. Since the material is applied under pressure, the rich cement mortar ensures dense compaction and stronger adhesion, and the treated surface becomes waterproof.
Cavity wall construction
This consists of shielding the building’s main wall by an outer skin wall leaving a cavity between them. The hole prevents the moisture from traveling from the exterior wall to the inner wall. Bathroom leakage solution is also a significant waterproofing process.