Active water leaks in concrete structures pose a significant threat to long-term durability. When left unaddressed, water intrusion can weaken structural integrity, accelerate the corrosion of embedded steel reinforcement, and lead to costly repairs. Concrete is naturally porous, allowing moisture to seep through cracks, joints, and unsealed surfaces. Over time, this moisture can cause rust, spalling, efflorescence, and freeze-thaw damage, further compromising the structure.
To effectively stop active leaks, it’s essential to choose the right repair method. Various solutions exist, each suited for different conditions and structural needs. Below are some of the most reliable techniques for sealing active water leaks in concrete.
Choosing the right approach to active water leaks is key to applying a permanent repair. Let’s take a look at some methods you could employ to stop active leaks in your own or your client’s structures.
Urethane Grout Injection
Urethane grout injection is a proven method for stopping active leaks in concrete. This process involves injecting a water-activated polyurethane grout into cracks, voids, or joints. Once the grout comes into contact with water, it expands, forming a flexible and watertight seal.
Best Use Cases:
- High-pressure leaks
- Leaks in moving or shifting structures
- Below-grade foundation walls, parking garages, and basements
Advantages:
- Reacts with water to stop leaks instantly
- Expands to fill voids and irregular spaces
- Remains flexible, accommodating minor structural movement
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Flexible Membrane Striping
For interior waterproofing, applying a flexible membrane to the surface of a structure can create a protective barrier against water intrusion. These membranes, made from urethane or polysulfide, adhere directly to the concrete, forming a continuous waterproof layer.
Best Use Cases:
- Interior surfaces of tanks, basements, and tunnels
- Areas where external excavation is not feasible
- Structures exposed to constant moisture
Advantages:
- Easy to apply to large surfaces
- Provides a seamless, durable waterproof barrier
- Works well in combination with other waterproofing methods
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Rout and Seal Cracks
Routing and sealing cracks is a traditional method for stopping water leaks in non-moving cracks. The process involves widening the crack slightly, creating a clean surface for better adhesion, and filling it with a flexible sealant or cement-based mortar.
Best Use Cases:
- Non-moving cracks in walls, floors, and ceilings
- Leaks caused by shrinkage or minor settlement
- Sealing cracks before they worsen
Advantages:
- Cost-effective and straightforward repair method
- Works well for fine and shallow cracks
- Can be combined with other waterproofing treatments
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Coat Interior of Structure
Applying a waterproof coating to the interior of a structure is an effective way to stop water infiltration. These coatings, made from cementitious or polymer-based materials, penetrate the surface and form a durable moisture barrier.
Best Use Cases:
- Basements, water tanks, and tunnels
- Preventing further moisture penetration in damp environments
- Areas requiring additional reinforcement against water exposure
Advantages:
- Strengthens concrete while preventing water intrusion
- Can be applied over existing coatings for added protection
- Resistant to wear and harsh environmental conditions
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Install Curtain Wall
Curtain wall injection is a specialized technique for stopping water leaks when external excavation is not possible. This method involves injecting a urethane grout behind the structure, creating a secondary waterproof barrier that prevents further water entry.
Best Use Cases:
- Below-grade foundation walls
- Structures where exterior access is limited
- Waterproofing without disrupting operations
Advantages:
- Eliminates the need for costly and disruptive excavation
- Creates an external waterproof barrier for long-term protection
- Works well for large or difficult-to-access areas
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Apply Crystalline Surface Treatment
Crystalline waterproofing treatments are designed to penetrate deep into concrete, where they react with water and unhydrated cement particles to form insoluble crystals. These crystals fill pores and micro-cracks, effectively blocking moisture pathways.
Best Use Cases:
- Waterproofing concrete from within
- Damp or minor leak-prone areas
- Long-term moisture resistance
Advantages:
- Forms a permanent waterproof barrier inside the concrete
- Works even in hairline cracks and porous areas
- Self-sealing capabilities enhance durability over time
Things to consider when selecting a method to repair active water leaks
Before selecting a repair method, several factors should be evaluated to ensure the best long-term solution:
- Severity of the Leak – High-pressure leaks may require urethane grout injection, while minor seepage can be addressed with crystalline treatments.
- Structural Conditions – Consider whether the structure is stable or subject to movement, as some repairs require flexible materials that can accommodate shifts.
- Repair Longevity – Some solutions offer temporary relief, while others provide a long-term fix. Choose a method that aligns with the expected lifespan of the repair.
- Accessibility – Some repairs, like curtain wall installation, are ideal for situations where exterior access is restricted.
- Environmental Factors – Exposure to extreme temperatures, chemicals, or constant moisture can impact the effectiveness of certain waterproofing solutions.
By choosing the right repair technique and applying preventative maintenance, active water leaks can be stopped before they cause significant damage. Addressing water intrusion early not only extends the life of the structure but also reduces the risk of costly future repairs.
