pu waterproofing

In the constant battle against the elements, protecting our buildings and structures from water damage remains a top priority. Liquid applied, polyurethane (PU) membrane waterproofing has emerged as a formidable tool against water leakage and structural deterioration. Offering a robust and versatile solution for a wide range of applications. This article delves into the world of Polyurethane (PU) waterproofing coatings, exploring its advantages, applications, and considerations for successful implementation.

Sunanda Global offers a variety of PU waterproofing solutions, and the products cater to various applications and are known for their:

High-Quality Materials: Sunanda utilizes cutting-edge PU formulations to deliver superior flexibility, adhesion, and weather resistance.

Proven Track Record: With over 45 years of experience (established in 1979), Sunanda Global has a proven record of success in waterproofing projects across India.

Innovation: We prioritize research and development, ensuring that PU waterproofing solutions are constantly evolving to meet the demands of the construction industry.

Understanding PU Waterproofing

PU, or liquid applied polyurethane membranes, are made of a synthetic polymer known for its excellent flexibility, strength, and adhesion properties. The liquid polyurethane coating, often applied in multiple layers, cures to form a seamless, elastomeric barrier that bonds tightly to the concrete substrate. 

The specific formulation of polyurethane (PU) used in waterproofing varies depending on the intended application and desired properties. Some key features to consider include:

Solvent-based vs. Water-based: Solvent-based PU offers superior adhesion and chemical resistance but can have stronger odor and environmental concerns. Water-based PU is more environmentally friendly but may have slightly lower performance characteristics.

Single-component vs. Two-component: Single-component PU is easier to apply and eliminates batching, weighing, and mixing at the site but may cure slower. Two-component PU requires mixing two components before application but offers faster curing.

Aromatic vs. Aliphatic: Aromatic PU offers high strength and chemical resistance, but may have slight discoloration over time. Aliphatic PU is UV-resistant and retains its color better, making it suitable for exposed applications.

The Benefits of PU Waterproofing

Compared to traditional waterproofing methods like asphalt or sheet membranes, PU offers several distinct advantages.

Superior Flexibility

PU membranes are highly elastic, allowing them to accommodate slight movements in the substrate without cracking or losing their seal. This is particularly beneficial for buildings that experience thermal expansion and contraction or are located in seismic zones.

Excellent Adhesion

PU forms a strong bond with various substrates, including concrete, brick, metal, and even existing waterproofing membranes. This eliminates the risk of water ingress through gaps or weak points.

Seamless Application

Liquid PU coatings can be applied to complex shapes and details, creating a continuous, watertight barrier. This eliminates the need for seams and reduces the risk of leaks in areas with intricate geometries.

Fast Curing

Most PU waterproofing systems cure quickly, minimizing downtime during construction or renovation projects.

Durability and Longevity

PU is known for its excellent weather resistance and can withstand harsh environmental conditions, including UV radiation, extreme temperatures, and freeze-thaw cycles.


PU waterproofing systems are lightweight compared to traditional methods, adding minimal weight to the structure.

Environmentally Friendly

While some PU formulations might have environmental concerns, advancements have been made toward water-based PU systems with lower VOC (Volatile Organic Compound) emissions.

Applications of PU Waterproofing

Rooftops: PU coatings and membranes provide excellent protection for flat roofs, balconies, and terraces.

Basements and Foundations: PU systems effectively prevent water seepage from the ground, protecting basements, retaining walls, and foundations.

Wet Areas: PU coatings are ideal for bathroom waterproofing, and waterproofing of kitchens, laundry rooms, and swimming pools.

Tunnels and Underground Structures: PU membranes offer superior waterproofing and resistance to hydrostatic pressure, making them suitable for tunnels, basements, and underground car parks.

Tanks and Reservoirs: These can be used to waterproof potable water tanks, wastewater treatment facilities, and industrial storage tanks.

Green Roofs: PU membranes can be used as a waterproof barrier beneath green roof systems, protecting the underlying structure from moisture damage.

Considerations for Successful PU Waterproofing

While PU offers a powerful waterproofing solution, proper application is crucial for optimal performance. Here are some key considerations:

Surface Preparation: The substrate must be clean, dry, sound, and free from contaminants such as oil, grease, or dust. Proper surface preparation ensures optimal adhesion of the PU membrane or coating. The moisture content of the surface should be less than 4% as measured by a digital moisture meter. 

Weather Conditions: Avoid applying PU waterproofing during rain, high humidity, or extreme temperatures. Follow the manufacturer’s recommendations for optimal application conditions.

Primer: In certain situations, a primer may be necessary to enhance adhesion and ensure compatibility between the PU system and the substrate.

Professional Installation: For complex applications or large projects, consider using qualified and experienced contractors for PU waterproofing installation. They can ensure proper application techniques and product selection based on the specific project requirements.

Maintenance: Regular inspection and maintenance are crucial to ensure the long-term performance of its systems. This may involve cleaning debris from the surface and checking for any signs of damage

PU waterproofing has emerged as a game-changer in the construction industry. Its versatility, superior performance characteristics, and long-term durability make it a compelling choice for a wide range of applications. Sunanda Global has leveraged PU waterproofing’s transformative potential to revolutionize the construction industry. Contact Sunanda Global today for expert polyurethane waterproofing solutions