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Building Resilience: 4 Advantages of PU injection waterproofing

During construction, it is essential for engineers and builders to maintain the structural integrity of the infrastructure they are developing and prevent moisture from seeping into the gaps and cracks of the foundation. One method commonly used for such applications is polyurethane (PU) injection grouting, also known as PU injection waterproofing.

This specific solution can effectively address various leaks and cracks, making it a go-to choice for reinforcing and stabilising structures. Let us share more details about this process and its advantages, exploring why it is a game-changer in the construction industry.

What Is PU injection waterproofing?

PU injection waterproofing is a process in which polyurethane (PU) resin is administered into the soil or cracks in concrete to fill them up. The aim is to strengthen the foundation of the infrastructure and prevent water from seeping through any potential openings within the structure.

Due to the PU resin’s effectiveness in sealing up cracks and stopping water leakage, it has become a popular choice for many construction projects, especially the development of tunnelling systems.

Understanding The Cause Of Cracks In The Structure

To maximise the effectiveness of PU grouting, it is crucial to understand the underlying causes of cracks and gaps in concrete structures. By identifying these issues, PU injection waterproofing can be strategically applied to the areas that are most at risk, preventing water damage and providing robust water protection for the infrastructure.

Cause #1: Bad Drainage

Moisture is often the primary cause of foundation cracks. The culprit is usually a bad drainage system that allows water to seep through, eroding the building materials and causing the foundation to become unstable. So, before injecting the PU grout into the structure, it is essential to check if the drainage system is working correctly.

Cause #2: Heavy Load

In industrial projects, heavy loads due to the movement of machinery and vehicles can cause cracks to form on the foundation of the structure after some time. The gaps are typically more severe in areas with a high traffic volume.

Cause #3: Wear And Tear

Over time, cracks and gaps will inevitably form due to wear and tear, especially if the structure is not well-maintained. This is especially true in areas that are constantly exposed to water and humidity.

PU Injection Repair Process

When applying the PU grout, each step must be executed correctly under expert supervision to ensure the best results. Here is a step-by-step guide below.

Step 1: Inspection

Before beginning the repair process, it is vital to check and analyse the area to determine the ideal location and spacing of the holes. If there are residue mineral deposits from the water leakage, please clear them before proceeding to the next step.

Step 2: Drilling

Drill short holes, otherwise known as ports, into the cracks at a regular interval to serve as entry and venting terminals for the PU resin. The minimum diameter and depth of the ports should be 1 cm and 10 cm, respectively. Meanwhile, the spacing between each hole should be approximately 150 mm c/c for finer cracks to 300 mm c/c for others. 

Additionally, the gap between each port should be kept greater than the desired depth of grout penetration. However, this can be adjusted depending on the actual situation and requirements for this particular project.

Step 3: Insert Packers

Subsequently, the technician will place a grouting nozzle injection packer into the drilled hole and tighten it with a hexagon wrench to ensure there is no gap between the nozzle and the drilling hole for the water to leak into.

Step 4: Seam Cleaning

Afterwards, the technician will utilise a high-pressure cleaning machine to inject clean water into the mechanical packers, cleaning any residue dust in the seam of the drilling area.

Step 5: Seal The Cracks

The surface of the cracks is sealed with a cement-based waterproof material during the washing stage to ensure the PU injection material does not seep out. 

Step 6: Grouting

Using a high-pressure grouting machine, the technician will inject the PU grout into the drilled holes, one at a time.

Step 7: Sealing

After the grouting is complete, the technician will remove the grouting nozzle if there is no more leakage and proceed to repair and seal the injected area with cement-based waterproof material. 

Advantages of PU injection waterproofing

Top Advantages of PU Injection Grouting

Advantage #1: Efficient and Cost-effective

Time and budget constraints are perennial challenges in construction projects. As extensive labour tasks and material costs pile up, resulting in increased expenses and prolonged timelines, many builders seek a cost-effective and time-efficient solution to ensure the structural integrity of the infrastructure they are developing without delaying the project further.

PU injection waterproofing offers a solution to these issues, as it requires minimal labour and is quicker to implement than traditional waterproofing methods since the PU resin hardens rapidly. The ease of application and reduced need for extensive groundwork make it an attractive option for small-scale repairs and large-scale construction developments.

Advantage #2: Highly Effective

Besides offering quick application, PU injection is also regarded as a highly effective and resilient waterproofing solution that can withstand the harshest weather and climate challenges. The PU resin is inherently resistant to water, ensuring the construction project remains impervious to leaks and water damage. Additionally, the flexibility of the material allows it to expand and contract with temperature fluctuations, preventing cracks and structural damage that can occur in extreme weather conditions.

Advantage #3: Highly Durable

Durability is essential in waterproofing systems. After all, the goal is to ensure the longevity of the structure. PU injection excels in this regard, offering sturdiness that stands the test of time. Renowned for its high strength and resilience, the PU resin makes the infrastructure more robust and capable of withstanding wear and tear, extending its lifespan and reducing the frequency of repairs and maintenance.

Advantage #4: Seamless Finish

Aesthetics can often be as crucial as functionality, especially in projects where the visual appeal of the infrastructure is a significant consideration. Fortunately, PU injection waterproofing is known to provide a seamless finish like no other, plugging any voids and gaps with precision. 

Due to its versatile and durable nature, PU injection waterproofing is evidently a worthwhile investment for fortifying structures long-term. It is one of many chemical grouting solutions in our portfolio to tackle complex leak-sealing issues, such as heavy water ingress and structure leakage. Contact us today to learn how we can help address the specific needs of your construction project.

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