Cracks in concrete structures aren’t just visually unappealing – they can become significant entry points for water and lead to long-term structural damage if left untreated. In Brisbane’s variable climate, with our regular periods of intense rain, this water seepage via cracks in concrete is especially common in retaining walls, basements, underground car parks, and concrete slabs. At Remedial Property Solutions, we offer a range of remedial waterproofing services – including crack injection sealing methods – that offer a highly effective solution for repairing leaks and restoring the effectiveness of your waterproofing membranes.

Keep reading to learn more about what causes concrete to crack, how we determine the best sealing method, and the differences between epoxy and polyurethane injection systems, including when to use high or low pressure. Alternatively, if you’ve noticed water leaking through a crack at your property – get in touch with our team of concrete injection waterproofing experts via our contact form to request a free onsite assessment anywhere in Brisbane, The Gold Coast or Sunshine Coast.

What Causes Concrete to Crack and Leak?

Over time, exposure to environmental pressures, construction faults, or structural movement can cause cracks to form within the concrete components of your property. One of the most common causes in Brisbane is soil movement due to expansive clay soils or poor drainage which places stress on the concrete to the point where it begins to fail. Shrinkage during curing, temperature fluctuations, or even vibrations from nearby works or traffic can also lead to cracking. Once concrete begins to crack, even if only minor, it becomes a vulnerable pathway for water intrusion—especially during wet weather or in areas with a high water table. Over time, repeated moisture exposure can cause the reinforcing steel to rust (concrete cancer) and ultimately weaken the concrete to a point where its structural integrity is compromised.

Determining the Right Crack Injection Sealing Method

Choosing the correct crack injection sealing method depends on several factors including; the width and depth of the crack, whether it is actively leaking, the level of movement expected, and the location of the structure (e.g., basement wall, suspended slab, or retaining wall). At Remedial Property Solutions, we begin every job with a detailed site assessment using non-invasive thermal water leak detection tools to determine the type of crack, moisture levels, and the underlying cause. From there, we recommend either epoxy or polyurethane injection depending on whether structural bonding or flexible waterproofing is required.

Epoxy Injection Sealing: For Structural Repair

Epoxy crack injection is ideal when the goal is to structurally bond the crack and restore the concrete’s original strength. Epoxy is a rigid, high-strength resin that penetrates deep into cracks and cures to form a solid, load-bearing repair. It’s most suitable for dry, dormant cracks in concrete load-bearing elements like beams, columns, and walls where movement is minimal. This method is not typically used in actively leaking or moving cracks, as the rigid nature of epoxy doesn’t accommodate future flexing. When applied properly, epoxy injection restores both the structural integrity and appearance of the concrete, making it a reliable long-term remedial solution.

Polyurethane Injection Sealing: For Concrete Waterproofing

Polyurethane injection sealing, often called PU injection, is the go-to method for sealing active leaks or cracks exposed to ongoing moisture or minor movement. Polyurethane expands upon injection, filling voids and sealing cracks even when water is present. As it reacts with the water, it forms a flexible, watertight seal that can still allow slight shifts in the structure without re-cracking. This makes it perfect for basement walls, retaining walls, underground car parks, or any area affected by hydrostatic pressure or fluctuating ground conditions.

At Remedial Property Solutions, we use high-performance polyurethane injection sealing resins designed for Australian conditions, delivering a permanent waterproofing barrier from the inside out—avoiding costly excavations to repair the failing positive side waterproofing membrane.

Low vs High Pressure Crack Injection Sealing Methods

The decision to use low or high pressure during injection sealing depends on the type of crack and material being used.

Low-pressure injection is generally used for hairline or superficial cracks, where gravity or slow pressure allows the resin to slowly permeate and fill the void. This method is ideal for delicate surfaces or vertical wall cracks in basements and can be controlled with minimal disruption.

High-pressure injection, on the other hand, forces the resin deep into finer cracks and behind the wall or slab to fill hidden voids, even when water is actively leaking. This is particularly effective for large retaining walls, slabs under pressure, or structures exposed to high moisture ingress. At Remedial Property Solutions, we use specialised injection equipment to safely and accurately apply pressure suited to each job, ensuring a thorough and lasting seal.

Contact Us To Discuss Your Crack Injection Repair Options Today

As Brisbane’s trusted experts in leak detection and structural repairs on commercial and multiresidential buildings, Remedial Property Solutions brings over 15 years of experience to every project.

Our team specialises in high-quality crack injection sealing and waterproofing services using proven techniques tailored to the exact requirements of each job. Whether you’re dealing with a leaking concrete rooftop, balcony or moisture entering your basement – we offer expert advice and fast, effective solutions with minimal disruption to your tennant or residents.

Get in touch with us now to request a free onsite quote.