Polyurethane Injection for Waterproofing & Leak Repair
What is Polyurethane Injection?
Polyurethane Injection is one of the most effective technologies for repairing water leaks and sealing concrete cracks and construction joints. The system works by injecting a specialized polyurethane resin into cracks and voids using professional injection pumps. Once the material comes into contact with water, it reacts rapidly and expands to form a closed-cell polyurethane foam that fills internal voids and permanently blocks water infiltration.
This system is capable of penetrating even the finest cracks and hidden water paths without extensive demolition, making it an ideal solution for active water leaks while preserving the integrity of the concrete structure and extending its service life. Polyurethane injection is widely used in basements, water tanks, tunnels, wastewater facilities, dams, canals, and other structures exposed to water ingress.
Why is Polyurethane Injection One of the Best Leak Repair Solutions?
Unlike conventional repair methods that only treat the surface, polyurethane injection seals the source of the leak from within the concrete. The injected resin penetrates cracks, joints, and internal voids before reacting with water and expanding to completely block water pathways, even under hydrostatic pressure.
Polyurethane resin provides excellent adhesion to concrete and performs effectively in both dry and wet cracks. It also minimizes the need for extensive demolition, allowing repairs to be completed quickly while maintaining the structural integrity of the building. These advantages make polyurethane injection one of the most reliable and efficient waterproofing repair systems available.
How Does Polyurethane Injection Work?
The process begins by identifying the location of cracks or active water leaks. Injection packers are then installed through strategically drilled holes to reach the internal crack path. A specialized injection pump is used to inject the polyurethane resin, allowing it to flow deep into the cracks, joints, and voids throughout the concrete structure.
When the resin comes into contact with water, it reacts immediately and expands to create a durable waterproof barrier that seals the leak from the inside. After the injection process is completed, the packers are removed and the drilled holes are repaired using a non-shrink polymer-modified repair mortar. Additional protective coatings may be applied when required to ensure long-term waterproofing performance.
System Advantages
Polyurethane injection is one of the most efficient solutions for waterproofing repairs, combining fast application with the ability to penetrate deep into cracks and internal voids within concrete structures. This provides a reliable and long-lasting solution for various types of water leakage. Key advantages include:
- Stops active water leaks directly at the source.
- Effectively seals cracks, construction joints, and internal voids.
- Reacts with water and expands to fill hidden leakage paths.
- Suitable for both dry and wet cracks.
- Provides excellent adhesion to concrete and structural substrates.
- Requires minimal demolition or concrete removal.
- Resistant to hydrostatic water pressure in below-grade structures.
- Helps protect reinforcing steel from moisture and corrosion.
- Suitable for both interior and exterior applications, including high-moisture environments.
- Fast installation with minimal disruption to facility operations.
- Extends the service life of concrete structures while reducing future maintenance costs.
- Effective for both fine hairline cracks and deep structural cracks.
Applications
Polyurethane injection is widely used in concrete structures affected by water leakage and cracking. It is suitable for both new construction and rehabilitation projects, including:
- Repairing active water leaks in concrete cracks.
- Construction joints and expansion joints.
- Basements and underground structures.
- Potable water tanks and underground reservoirs.
- Wastewater treatment plants and sewage tanks.
- Tunnels and underground infrastructure.
- Dams and water canals.
- Manholes and utility chambers.
- Gas and oil pipeline systems.
- Soil stabilization and void filling beneath foundations.
- Residential, commercial, and industrial concrete structures exposed to water ingress.
Application Process
1. Inspection & Surface Preparation
The process begins with a detailed site inspection to identify leakage points and crack locations. The affected area is then cleaned by removing loose materials and contaminants to ensure the concrete substrate is ready for injection.
2. Crack Preparation
Cracks are prepared as required by removing dust, debris, and loose particles. Damaged concrete and exposed reinforcement, if present, are repaired before injection to ensure optimum system performance.
3. Injection Packer Installation
Injection packers are installed through strategically drilled holes along the crack line. Their spacing and depth are selected according to the crack geometry to ensure complete resin penetration throughout the leakage path.
4. Polyurethane Resin Injection
The polyurethane resin is injected using a professional injection pump operating at pressures of up to 150 bar. The resin penetrates the crack network, reacts with water, and expands to form a waterproof barrier that permanently seals the leakage path.
5. Finishing & Final Protection
After the injection process is completed, the injection packers are removed and the drilled holes are sealed using a non-shrink repair mortar. Additional protective or waterproofing systems can be applied where required to ensure long-term durability and performance.
Materials Used in the Injection System
The efficiency of the polyurethane injection system depends on selecting the appropriate materials based on the type of crack, the severity of water leakage, and site conditions. The system utilizes a high-performance polyurethane injection resin that reacts with water to form an expanding foam, sealing cracks and internal voids while preventing further water ingress. Specialized injection pumps and injection packers ensure that the resin reaches every leakage path, while suitable repair mortars are used to seal the injection holes after the work is completed.
Technical Specifications
| Item | Specification |
|---|---|
| System Type | Polyurethane Chemical Injection |
| Injection Material | Polyurethane Resin |
| Application Method | Injection using a specialized injection pump |
| Injection Pump Type | Mechanical or Hydraulic Injection Pump |
| Pump Pressure | Up to 150 bar |
| Injection Pressure | Up to 30 bar (depending on concrete condition) |
| Reaction Mechanism | Reacts upon contact with water |
| Expansion Ratio | Expands up to 30–40 times its original volume when exposed to water |
| Foam Type | Closed-Cell Polyurethane Foam |
| Solvent Content | 100% Solvent-Free |
| Primary Application | Water leak sealing and concrete crack repair |
| Applications | Cracks, construction joints, basements, tunnels, water tanks, dams, canals, and soil stabilization |
| Water Resistance | Excellent after full curing |
| Suitable for | Interior and exterior applications |
Frequently Asked Questions
Can polyurethane injection stop active water leaks?
Yes. Polyurethane injection is specifically designed to seal active water leaks. The resin reacts with water, expands inside the crack, and forms a durable waterproof barrier that prevents further leakage.
Does the injection process require concrete demolition?
In most cases, no. Only small holes are drilled to install injection packers, eliminating the need for extensive demolition while preserving the structural integrity of the concrete.
Can polyurethane injection be used for both dry and wet cracks?
Yes. Polyurethane resin is suitable for repairing both dry and wet cracks and performs effectively even in active water leakage conditions and under hydrostatic pressure.
Where can the polyurethane injection system be used?
The system is suitable for basements, water tanks, wastewater treatment facilities, tunnels, dams, canals, manholes, utility structures, and various reinforced concrete structures affected by water leakage.
Is polyurethane injection a permanent repair solution?
When the appropriate injection material is selected and the system is installed according to technical specifications, polyurethane injection provides a long-term solution for water leakage repair. The overall performance also depends on addressing the root cause of the leakage when necessary.
Why Choose EMC?
At EMC, we specialize in advanced polyurethane injection systems for concrete crack repair and water leakage treatment, using high-quality materials, professional injection equipment, and experienced technical teams to deliver reliable and long-lasting waterproofing solutions.
Our approach begins with a thorough site inspection to identify the source of leakage, followed by selecting the most appropriate injection system for each project. Every application is carried out in accordance with industry best practices to ensure effective sealing of water ingress while preserving the structural integrity of the concrete. This enables us to provide durable, efficient, and cost-effective repair solutions for residential, commercial, industrial, and infrastructure projects.