7 Common Waterproofing Materials Used In Singapore

Updated: Aug 3

Various waterproofing materials can be used, depending on the situation at hand. Several variables that need to be considered are the material of the surface being applied to, the budget of the project and the type of structural damage that has occurred. A competent waterproofing contractor will take time to understand both the structure and the client's needs before recommending a waterproofing method to fix the problem.


Cementitious Waterproofing

Also known as cementitious coating, cementitious waterproofing is the most popular method worldwide for waterproofing concrete structures. The cementitious coating is a form of a powder that consists of sand, organic and inorganic chemicals, and silica-based substances. When the active ingredients are combined with lime, it causes a hydration reaction, creating a waterproof seal. The reason cementitious waterproofing is highly popular is due to its ease of application process. However, cementitious insulation lacks flexibility. As mentioned, cementitious waterproofing methods are used for concrete structures such as concrete walls, foundations, sidewalks and walkways. It can be applied in either spray or liquid forms, depending on where it will be applied. Spray formulas are ideal for smaller surfaces, while liquid formulas work better for larger surfaces. Additionally, the cementitious coating provides anti-corrosion properties to substrates; for instance, steel within the structure is protected from corrosion by maintaining a pH level above 4.0 at the coating interface as steel corrodes at a slower rate in this pH range.

Polyurethane Liquid Membrane

Also commonly abbreviated as PU, it is one of the most common waterproofing materials used. Polyurethane offers a seamless waterproofing membrane and seal; it can fill capillary cracks extremely well while decreasing the concrete's water absorbency. One thing to note is that polyurethane tends to harden the concrete’s uppermost surface as it penetrates the surface very deeply.

Polyurethane liquid membrane can be applied to many structures such as flat roofs, pedestrian decks, water tanks, ponds, balconies, roofs, bridges, parking decks and other areas that are continuously exposed to the elements. Polyurethane can resist water well and will not cause any joints or leak risk areas. The material is water vapour permeable, too; this allows water vapour to pass through the membrane. It will provide adhesion for the full surface. Another thing to note is that polyurethane is great because it can resist oils, detergents, and other chemicals. In outdoor applications, this method is more effective than cementitious waterproofing. Polyurethane has an average working life of 25 years or so, ensuring that your building is protected for a long duration. However, do note that there are some risks when handling polyurethane as this material can be dangerous. If left uncured, polyurethane fumes can cause asthma and other breathing problems such as throat and eye irritation, headache, nausea and shortness of breath. If the material touches the skin, there is a risk that you’re going to experience skin sensitivity and irritation. They might be short or long term. It’s pertinent to let a professional waterproofing specialist handle the application process.


EPDM Rubber

Ethylene propylene diene monomer or EPDM rubber is a synthetic rubber that is extremely durable and flexible. This rubber has a wide range of waterproofing applications and is a popular choice for waterproofing roofs. It is typically applied to other materials such as vapour barriers and thermal insulation on rooftops to provide waterproofing capabilities. The rubber also has high tensile strength, making it an ideal material for rooftops where the environment may subject it to extreme heat, UV rays and rain. EPDM can be formulated to resist temperatures as high as 150°C and can be used outside for many years or decades without degradation.

Bituminous Coating Membrane

Also known as asphalt, bituminous is a sticky, highly viscous liquid made using asphalt or coal tar. Bituminous waterproofing has many applications in both residential and commercial buildings. Like liquid membranes, it's flexible, viscous and adheres to certain materials exceptionally well due to its formulation, making it waterproof enduring. It is commonly used to waterproof roofs, basements, below-ground structures, bridges and more.


The downside to using this material is that when exposed to extreme temperatures and UV radiation, its lifespan decreases significantly. Furthermore, bituminous is combustible and releases toxic fumes during application. A waterproofing specialist will have the necessary safety precautions and equipment to apply this membrane safely and effectively.

Bituminous Coating Membrane
Hydro-seal Engineering Technicians Applying Torch-on Membrane to bituminous coating

PVC Waterproofing Membrane

PVC, or polyvinyl chloride, is another commonly used waterproofing material used primarily in roofing, swimming pools and underground structures. The PVC waterproofing membrane is known as a modern roofing material, which is made of high quality flexible (plasticized) polyvinyl chloride. It is a highly water-resistant material that ensures water will not penetrate the structure. Additionally, it is vapour permeable, allowing water vapour to escape easily and reducing the risk of moisture accumulation.


The reinforcing base of PVC waterproofing membranes is normally made of glass fibre or polyester mesh. There are typically two types of PVC waterproofing membranes - reinforced or unreinforced. Both types of membranes have their benefits. Reinforced membranes are more durable, while unreinforced membranes are more flexible. PVC waterproofing membranes are popular due to their ease of installation and long-lasting life.


Thermoplastic

Thermoplastic, or thermosoftening plastic, is highly sought after in waterproofing projects as it is one of the strongest waterproofing materials available. It is resistant to abrasions and tears, has excellent bending and tensile strength, large elongation break, low-temperature resistance, low long-term deformation rate, and is resistant to chemicals, ozone, oxygen, oil, and fuel.


Thermoplastics can provide, on average, up to 50 or more years of waterproofing durability. Furthermore, it maintains the base materials flexibility and softness too. These characteristics combine to produce technical textiles that withstand extensive wear and environmental stressors across hundreds of applications. Thermoplastics are applied by heating the solid rubber pallets into a semi-solid slate and applied accordingly. The main downside to using thermoplastics is the relatively higher cost as compared to other materials.


Liquid Applied Membrane

Liquid applied membrane, commonly abbreviated as LAM, is a liquid-based waterproofing coating used commonly in roofing applications. The liquid is sprayed on and cures in the air to form a seamless, rubber-like elastomeric waterproof membrane and may be applied over many substrates, including asphalt, bitumen and concrete.


The benefit of LAM is that it is joint-free, and the membrane's thickness can be controlled by applying multiple coatings. Due to the ease of application, the process can be performed quickly to avoid cold joints. However, proper care must be taken during the application to provide just the right thickness as the membrane can tear or break if it is too thin. LAM is also very durable and cost-effective, especially for roof renovations and waterproofing. It is also vapour-permeable.

Liquid Applied Membrane
Hydro-seal Engineering Specialists Applying Liquid Applied Membrane

Contact Hydro-seal Engineering

Hydro-seal Engineering has assisted residential & commercial clients with their waterproofing needs since 1995. Contact us at 6289 6811 for a free consultation and diagnosis of your property.