Waterproofing in buildings is the formation of an impervious barrier over surfaces of foundations, roofs, walls and other structural members of building to prevent water penetrations through these surfaces. The building surfaces are made water-resistant and sometimes waterproof.
Commonly used materials for waterproofing in building is cementitious material, bituminous material, liquid waterproofing membrane and polyurethane liquid membrane etc.
Waterproofing in buildings and structures are generally required for basement of structure, walls, bathrooms and kitchen, balconies, decks, terrace or roofs, green roofs, water tanks and swimming pools etc.
Walls
Terrace / Balcony / Canopy / Roof deck
Basement / Wall and matting
Ground Slabs
Landscape Deck
Tanks and Cisterns
Portable Water Reservoirs
Swimming Pools
Planter Box
1. Cementitious Waterproofing Method
Cementitious waterproofing is the easiest method of waterproofing in construction. The materials for cementitious waterproofing is easily available from suppliers of masonry products, and they’re easy to mix and apply.
This method is often used in the internal wet areas such as toilets. This method is usually a rigid or semi-flexible type waterproofing, but since it is used in internal areas such as toilets, it is not exposed to sunlight and weathering. Thus cementitious waterproofing does not go through contract and expansion process.
2. Liquid Waterproofing Membrane Method
Liquid membrane is a thin coating which consists of usually a primer coat and two coats of top coats which are applied by spray, roller, or trowel. It offers more flexibility than the cementitious types of waterproofing.
The liquid cures into a rubbery coating on the wall. The elongation properties of the coating can reach as high as 280%. The durability of the waterproofing coating depends on what type of polymer the manufacturer use for the making of the liquid waterproofing.
Liquid waterproofing membrane can be of spray-applied liquid membrane composed of polymer-modified asphalt. Polyurethane liquid membranes in separate grades for trowel, roller, or spray are also available from various manufacturers.
3. Bituminous Membrane Waterproofing Method
Bituminous membrane waterproofing is a popular method used for low-sloped roofs due to their proven performance. Bituminous waterproofing membrane have torch on membrane and self-adhesive membrane.
Self-adhesive compounds comprise asphalt, polymers and filler; additionally, certain resins and oils may be added to improve adhesion characteristics. The self-adhesive type has low shelf life as bonding properties of the membrane reduces with time.
Torch on membrane have exposed and covered types. Exposed membrane often has mineral granular aggregate to withstand the wear and tear of the weathering and the other types of membrane, contractor need to apply one protective screed to prevent the puncture of the membrane.
Epoxy floor coating systems are made up of two distinct elements: an epoxy resin and a polyamine hardener. These two components are mixed prior to application. When the resin and the hardener are combined, they engage in a chemical reaction that creates cross-linking of the elements as it cures. The result of the chemical reaction is a hardened, rigid plastic coating material that bonds well to most base layers.
Epoxy floor coatings are known for their hardness, durability and impact resistance. These characteristics make epoxy coatings ideal for heavy-duty applications such as industrial facilities, warehouses, logistic centers and other areas that may be subjected to heavy forklift traffic. Epoxy is also known for its resistance to chemical products, such as bleach, oils, greases, cleaners, etc. This chemical resistance makes them a popular choice in garages in the automotive industry.
Types of Epoxy Floor Coatings
1. Polyurethane Floor Coatings
Polyurethanes are polymers that are connected to a chemical compound group known as carbamates. Polyurethane is a thermosetting polymer by nature; i.e., it does not melt when heated. To the untrained eye, polyurethane coatings may appear to be visually similar to epoxy coated floors. However, they possess distinct characteristics that make them ideal for specific applications.
Unlike epoxy coatings, which are highly stiff and impact-resistant, polyurethane floor coatings are relatively softer and more elastic. This attribute makes polyurethane floor coatings better suited for areas with moderate to heavy pedestrian traffic. The increased elasticity also makes polyurethane-coated floors more resistant to abrasion, since impact loads are easily absorbed and less prone to cause scratches. The elasticity and flexibility of polyurethane also contribute to their ability to operate in environments with low freezing temperatures.
The desirable characteristics of polyurethane floor coatings make them ideal for several applications, including car parks, freezing chambers and busy commercial facilities, such as shopping malls, airports and hospitals.
One of the other significant advantages of polyurethane floor coatings is their curing time. Floors coated with this material can be ready for operation the next day. In contrast, epoxy coatings need at least seven days to cure before they can be ready for use.
While polyurethane possesses many beneficial properties, they do have a few shortcomings. Firstly, polyurethane floors are highly sensitive to moisture. When moisture attacks the floor, bubbles can form on the surface, causing unsightly blemishes on the surface. Polyurethane floor coatings are, therefore, not recommended for use in areas with high levels of humidity. Their limited pot life and moisture sensitivity also make them challenging to work with. As such, the proper handling and application of polyurethane coatings usually require well-trained and knowledgeable staff.
2. Polyaspartic Floor Coatings
Polyaspartic is a subset of polyurea. (More information about polyurea coatings can be found in the article The History and Industry Adoption of Polyurea Coating Systems.) Like polyurea floor coatings, polyaspartic is a two-part system, i.e., the resin needs to be combined with a catalyst to facilitate the curing and hardening process. While early variations of polyaspartic floor coatings possessed several shortcomings, innovations in coating technology have made these floor coatings a versatile alternative to epoxy and polyurethane coating systems.
One of the primary benefits of polyaspartic is its ability to be used as a complete flooring system as well as a topcoat. In other words, polyaspartic floor coatings can achieve in a single coat what traditional epoxy and polyurethane would normally take two coats to accomplish. As a result, polyaspartics can significantly reduce application times, labor and material costs.
Another benefit of polyaspartic floor coatings is its ability to be customized. Polyaspartic esters can be manipulated to control drying times and pot life. This characteristic lessens lag time and allows assets to be put back into service faster. Some coating formulations can dry in a matter of hours, with a next-day return to service.
Because polyaspartic floor coatings meet or exceed some of the properties of their polyurethane counterparts, they can be used in many of the same applications. These primarily include areas with medium to heavy foot traffic, such as airports, malls, shopping centers, hospitals, etc.
Similar to epoxies, polyaspartic floor coatings require careful attention to surface preparation. Improperly prepared surfaces can result in various types of coating failure. Also, while polyaspartic coatings with 100% solids have low volatile organic compound (VOC) emission rates, most polyaspartics are solvent-based. These solvent-based coatings can be dangerous to inhale; therefore, skilled labor and appropriate respiratory equipment are required during application.
3. Acrylic Floor Coatings
Most acrylic floor coatings are made with more than one monomer, such as ethyl acrylate, methyl methacrylate or butyl acrylate. These components are often processed in a solvent, usually water. These floor coatings offer a middle ground in terms of cost and performance.
Acrylic floor coatings are not as durable as their epoxy or polyurethane counterparts. As such, they may need to be buffed or recoated more frequently than other coatings. Therefore, while the initial cost of acrylic floor coatings may be relatively inexpensive, long-term maintenance costs tend to be higher than those for other coatings.
Due to these shortcomings, acrylic floor coatings are best suited for decorative concrete, surfaces with minimal foot traffic, and areas with minimal risk of abrasions or chemical spills. Specific acrylic formulations, however, can offer superior performance characteristics, such as enhanced UV protection, slip resistance and water resistance.
While acrylic lacks the durability of other floor coatings, they possess relatively fast curing times, drying as fast as an hour after application. This reduces the overall labor requirements and turnaround times. Additionally, the surface of the coating can be easily buffed in the event the coating becomes damaged during operation.
