How to Select the Correct Injection Resin for Your Project

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Written by Warren Muschialli

Injection resins are a cornerstone of modern construction and waterproofing, offering versatile solutions for sealing water leaks through cracks, defects and construction joints within below-ground structures.

For engineers and contractors working on basements, tunnels, or other underground structures, injection resins provide a reliable and durable method to address challenges with water ingress. However, selecting the correct resin for your project is critical to achieving long-lasting results.

This blog explores the scenarios where injection resin is the best option, compares Newton’s high performance acrylic and polyurethane injection resins, and offers practical advice on selecting the right product for your needs.

Key Scenarios for Injection Resin Applications

Injection resins are particularly effective in situations where surface leak-sealing methods are impractical or insufficient. Below are three common scenarios where an injection resin can be the ideal solution:

1. Sealing Movement or Isolation Joints

Movement and isolation joints are designed to accommodate expansion, contraction and even sheer movement, often where a new structure tightly abuts an existing structure. Although British Standard 8102:2022 expressly recommends that they should be avoided where possible, in many cases they are included to isolate dynamic loads from impacting adjoining structures, or where settlement is expected.

Because these joints are difficult to waterproofing effectively, they often leak and often the only option is to seal using resin injection techniques. By selecting injection resins that exhibit the required levels of flexibility, it is possible to ensure an elastic and watertight solution that can be applied with minimal disruption to operations.

Why an injection resin is ideal for movement joints:

• Flexibility: Certain acrylic resins can adapt to joint movement without compromising their waterproofing integrity.
• Minimal downtime: Repairs can be carried out to the structure, often without too much disruption to operations.
• Precision application: Curing times can be adjusted to ensure the accurate placement and swift sealing of the joint.

2. Sealing Leaks Through Cracks and Construction Joints

Whether the leak is through a construction joint or through hairline cracks, it is common to experience leaks through reinforced concrete structures. However, they can be easily and quickly sealed using injection resins.

Depending on the size and nature of the leak and the level of water ingress, there are different types of injection resins that can be used, either in isolation or as part of a system to effectively seal the leak. For example, a defect that is experiencing high volumes of water ingress will first require the leak to be stemmed before it is fully sealed.

Comparing Injection Resins

Resins fall into three basic categories:

1. Leak stemming: High-foaming resins that quickly react with water to seal against even very high volumes of water ingress
2. Leak sealing: Non-foaming resins with low or no reaction with water to seal deep into the joint, often after initial stemming with a high foaming resin.
3. Hybrid: Resins that can both stem the flow of water and also fully seal the joint.

The following products are just two examples from our range of resin products thanks to our partnership with injection resin specialists TRADECC.

PC Leakinject UNI 6816 E

PC Leakinject UNI 6816 E is a single-component high-foaming polyurethane resin designed for Stage 1 rapid containment of high-pressure water leaks. Its closed-cell foam expands up to 2200% in contact with water, effectively stemming active leaks even in challenging conditions such as basements or tunnels experiencing significant water ingress.

Key features:

• Primary use: Stage 1 containment of high-water-flow leaks.
• Viscosity: High foaming for rapid expansion upon contact with water.
• Cure time: Quick cure within minutes.
• Ideal applications: Emergency leak control in basements, tunnels, or other underground structures.

PC Leakinject 2K Flex 6811 LV

PC Leakinject 2K Flex 6811 LV is a two-component, low-viscosity polyurethane injection resin designed for Stage 2 precision sealing of cracks and joints with low water pressure. This may follow the initial Stage 1 leak containment using PC Leakinject UNI 6816 E as detailed above.

The low viscosity and longer curing time of the 2K Flex 6811 LV ensures that it penetrates deep into the cracks and pores of the concrete, before reacting with or without the presence of water to create a flexible seal.

Key features:

• Primary use: Stage 2 sealing of cracks and capillaries.
• Viscosity: Low viscosity ensures deep penetration into substrates.
• Cure time: Adjustable via catalyst ratios.
• Ideal applications: Final sealing of concrete cracks after initial leak control.

How Do You Select the Right Injection Resin?

Selecting the correct injection resin depends on factors such as leak severity, substrate conditions, crack behaviour (static vs dynamic), and environmental constraints like temperature resistance or chemical exposure.

Different injection resins with different qualities may also be used in combination to deliver a completely sealed structure in different stages, from the temporary stemming of high volumes of water to creating a permanent, watertight seal.

Best Practices for Injection Resin Application

To ensure successful application of injection resin in waterproofing or structural repair projects, follow these best practices:

1. Injection Packer Placement: Install injection packers at regular intervals (150–300 mm) along cracks or defects to ensure even distribution of resin.
2. Mixing Resins Correctly: Use dual-component pumps or mixers to achieve precise catalyst ratios based on site-specific conditions such as temperature and water pressure.

Delivering Reliable Solutions with Injection Resin

Injection resins contractors with a versatile, fast reacting solution for addressing waterproofing challenges in basements, tunnels, and other underground structures across the UK. Whether you’re sealing leaking movement joints, or preventing water ingress through concrete defects, choosing the right injection resin is critical to achieving long-term durability.

Our range of injection resins offers exceptional performance tailored to your specific project requirements.

For expert advice on selecting the right injection resin for your project or assistance with waterproofing solutions tailored to your needs, contact Newton Waterproofing’s technical team today.