.png){kind=small}
Why PU Grouting Is a Smart Waterproofing Choice for Singapore Properties
- Earnest Lim
- Oct 26, 2021
- 5 min read
Updated: Jun 14
TL;DR: Is PU Grouting Right for You?
Ideal for Singapore’s tropical heat and rainfall
Seals narrow gaps and cracks in concrete structures
Flexible and durable against UV rays and thermal changes
Great for rooftops, facades, and foundations
Long-term waterproofing with low maintenance
Table of Content
The Hidden Leaks Lurking in Singapore Homes
From sudden downpours to year-round humidity, water is a constant challenge for property owners in Singapore. Tiny cracks in concrete can lead to costly leaks, ceiling stains, or worse—structural damage. That’s where PU grouting comes in.
Short for Polyurethane grouting, this method is popular for its flexibility, strength, and ability to seal even the finest of gaps. Whether you're managing a high-rise condo or a landed property, PU grouting is one of the most reliable waterproofing solutions in Singapore.
What Is PU Grouting and How Does It Work?
PU grouting involves injecting a liquid polyurethane mixture into cracks, voids, or joints in concrete. Once it comes into contact with moisture, the material expands and solidifies into a flexible yet tough seal.
Unlike rigid materials like epoxy, PU grouting offers elasticity that can withstand structural movements. It adheres strongly to most substrates, making it suitable for dynamic environments like building exteriors and rooftops.
PU Grouting is a mix of Polyurethane (PU) and cementitious materials that have similar properties to concrete but can be pumped into narrow spaces. The product takes advantage of the high tensile strength and impermeability of PU; it also features impressive low modulus capabilities compared to other materials used in construction.
In addition, PU injections can easily bridge gaps to fill the space between two surfaces. The elastic nature of PU injections provides resistance to thermal expansion, in a hot climate in Singapore, building rooftops and balconies are often exposed to harsh sunlight. Additionally, PU injection methods have additional properties to reduce deterioration due to long-term exposure to sunlight.
PU Grouting at its best features powerful adhesion, can be applied under compression, has resistance to most chemicals and fluids used in the waterproofing industry, is watertight, resistant to impact, will not crack or tear under tension or shear stress. Its self-levelling properties mean that it won't sag over time like other injection materials. It's perfect for filling voids in rooftops, building facades, concrete foundations, and waterproofing in general.
Why Choose PU Grouting in Singapore’s Climate?
Handles Heat Well: PU's low thermal expansion helps it stay intact despite hot days and cooler nights.
UV Resistant: Perfect for rooftops and balconies, it doesn’t crack or fade under strong sunlight.
Moisture Adaptive: PU grouting reacts with water to expand and seal gaps—ideal for our wet climate
As its name implies, PU Grouting is an excellent waterproofing option for construction projects. The material creates a watertight seal that protects structures from moisture damage. It can also serve as a protective coating against corrosion, making it an appealing choice for many types of building projects.
Building rooftops are especially vulnerable to the effects of moisture, which can damage the supporting structure over time. PU Grouting coats exposed areas, filling gaps and cracks that would otherwise let water get through. The coating provides a complete seal against moisture while remaining flexible enough to adapt to variations in temperature and humidity levels.
Where Can PU Grouting Be Used?
PU grouting is extremely versatile:
Concrete rooftops and balconies
External building facades
Basement walls and foundations
Lift pits, water tanks, and tunnels
Between concrete slabs or construction joints
Its self-levelling nature allows it to fill uneven spaces completely, making it especially valuable for complex or inaccessible areas.
How Long Does PU Grouting Last?
With proper application, PU grouting can last for many years. It remains flexible, resists chemical and UV damage, and doesn’t sag or shrink over time.
Bonus: The presence of moisture actually helps the PU material stay elastic—a benefit in humid Singapore
Polyurethane grouting remains intact so long as there is a continuous supply of fresh material to replace any loss from wear and tear, chemical degradation, or physical damage. The presence of water in the grouting mix helps extend its lifespan since it keeps the PU thermoplastic material flexible.
PU grouting materials are also resistant to deterioration caused by exposure to ultraviolet light; they won't ever fade, crack, chip, or peel over time. This makes them a great choice for use in high-stress environments and other areas with high exposure to the elements.
Is PU Grouting Suitable for My Project?
If your property has any of the following, PU grouting could be the right fit:
Cracks in concrete floors or walls
Water seepage from rooftop or balcony
Structural movement causing joint separation
It's also commonly used in infrastructure projects like MRT tunnels, reservoirs, and power stations.
As a waterproofing material, PU grouting has a plethora of benefits that make it an attractive option for many different projects. This includes both interior and exterior projects, in addition to applications in transportation, utilities, energy production, mining construction, and more.
PU grouting is an excellent option for filling cracks in concrete surfaces before applying waterproofing material or coatings. It's also useful in wall construction where it fills the space between two concrete slabs, providing an airtight water barrier.
What are the benefits of PU Grouting?
It's flexible, durable, and strong. It has a low coefficient of thermal expansion to prevent damage from temperature fluctuations. It resists chemicals used in marine environments and will not crack or chip under UV exposure. Its self-levelling properties allow it to fill gaps and distribute weight evenly. Polyurethane injections are a versatile solution for waterproofing construction projects in Singapore.
Professional Application vs DIY
While PU grouting kits exist, professional application ensures:
Proper identification of leak points
Controlled injection pressure
Long-lasting results with no recurrence
At Hydro-seal Engineering, our technicians use high-pressure pumps and thermal imaging to accurately locate and treat affected areas.
Get Waterproofing Right with Hydro-seal Engineering
Since 1995, Hydro-seal has delivered trusted waterproofing solutions across Singapore. Our PU grouting service is ideal for:
Commercial buildings
Condominiums and MCST-managed properties
Private landed homes
📞 Request a Free Site Inspection at +65 6289 6811.
FAQs: PU Grouting in Singapore
What is PU grouting used for? It’s used to seal cracks, fill voids, and prevent water ingress in concrete structures.
How long does PU grouting last? Properly applied, it can last for years, even in harsh outdoor environments.
Is PU grouting safe? Yes, it’s a non-toxic, non-corrosive material once cured.
Can it be used during rainy weather? Yes—in fact, moisture helps the PU expand and cure more effectively.
What’s the difference between PU grouting and epoxy injection? PU is flexible and ideal for waterproofing; epoxy is rigid and better for structural repairs.