There are various methods of waterproofing based on the areas of application like basements, roofs, tanks, treatment tanks, planter boxes, kitchens and other wet areas, The main methods of waterproofing can be broadly classified as:
- Cementitious coatings
- Flexible polymer coatings
- Bituminous coatings
- Prefabricated bitumen membranes
- Prefabricated rubber membranes
- Prefabricated thermoplastic membranes
Let us have a brief description of the above methods one by one.
- Cementitious Coatings
These are a blend of Portland cement and polymer binders such as Styrene Butadiene Rubber (SBR), Polyvinyl Acetate (PVA) and other such polymers. These may consist of either single or 2 components. They have a better compressive strength than other liquid coatings and are mixed with water or with the given polymer in 2 component systems. These coatings are applied with brushes, squeegees, rollers or using spray machines.
Areas of Application
These coatings are mainly used in bathrooms, bridges, walkways, water tanks, dams, balconies, kitchens and other wet areas.
- Flexible Polymer Coatings
These are a blend of different polymers which have more flexibility and elongation than the cementitious coatings. These can either consist of 100% solid content or blended with fillers and solvents. These coatings may be based on polymers acrylic, polyurethane, epoxy, polyurea and the like. These coatings are mainly used where flexibility and elongation properties are required, and these coatings have crack
bridging capabilities.
Areas of application
These coatings are mainly used in bridges, roofs, water tanks, dams, balconies, kitchens and other wet areas.
- Bituminous Coatings
These coatings are based on bitumen mainly derived from refining petroleum products, and these coatings may be either water or solvent based emulsions and are selected based on the areas of application.
Areas of application
These coatings are mainly used for substructures where there is no water table and as damp proofing course. They are also being used as a protective coating over the insulation layers like polyurethane foam as a part of a combo system.
- Prefabricated Bitumen Membranes
These are bitumen membranes modified with polymers and are produced as rolls to a predetermined length, width and thickness in the factory. The most common types of these membranes are modified Styrene Butadiene Styrene (SBS) and Atactic Polypropylene (APP). The APP membranes are usually used in exposed structures, whereas the SBS membranes are used in areas usually not exposed to sun. These
membranes are laid over a primer using butane torches and the joints are welded. Compared to other coatings, the application of these membranes requires skilled workers.
Areas of application
These membranes are mainly used in roofs, deep basements, bridges, bathrooms
and wet areas.
- Prefabricated Polymer Membranes
These are factory made membranes made of different rubbers and plastics cut to required sizes and supplied. The main types of these membranes include:
Ethylene Propylene Diene Monomer (EPDM)
Hypalon rubber .
These membranes are installed over an adhesive and the joints are sealed using
rubber compounds and tapes.
Areas of application
These membranes are mainly used in roofs, podiums, basements, artificial lakes and
corrugated sheet roofing.
- Prefabricated Thermoplastic Membranes
These are usually referred to as geomembranes and are supplied as rolls to specific sizes and the main types of these include:
High Density Polyethylene (HDPE)
Polyvinyl Chloride (PVC)
Thermoplastic Polyolefin (TPO)
These membranes are usually laid freely over the substrate and the joints are welded using hot air guns and extrusion equipment.
Areas of application
These membranes are mainly used in deep basements, artificial lakes, roofs,
podiums, and sheet roofing systems.
