1800 18 20 20

Rectifying Subsidence Issues For Five Houses in Pascoe Vale

Project Overview:

In the realm of construction and property development, ensuring the structural integrity of buildings is paramount. This case study delves into the challenges faced by a chemical underpinning company tasked with rectifying subsidence issues in five houses, caused by poor drainage and construction practices. The project involved the utilization of injection works both internally and externally to lift and close the cracks, ultimately restoring stability to these properties.


The five houses in question were constructed using waffle pod slab foundations, a common choice due to its cost-effectiveness and efficiency. However, during the assessment phase, it was evident that the subsidence issues were linked to two primary factors: poor drainage systems and subpar construction practices. The houses exhibited cracks on both interior and exterior walls, uneven flooring, and doors and windows that no longer operated smoothly.

Project Scope:

  1. Site Assessment: The initial phase involved a comprehensive assessment of each property. This included soil analysis, drainage system inspection, and a thorough examination of the foundation structure. It was revealed that the waffle pod slabs had settled unevenly due to inadequate soil compaction and drainage problems, leading to differential settlement and subsidence.

  2. Solution Design: To rectify the subsidence issues, a multi-faceted approach was designed. This involved the injection of specialized chemical grouts, both internally and externally, to raise and stabilize the affected areas. Additionally, improvements were made to the drainage systems to prevent future subsidence problems.

  3. Implementation: The injection works were executed systematically. Internal injections targeted the areas where cracks had formed, while external injections were performed along the perimeter of each house to lift and level the foundation. This process was carried out under the supervision of experienced engineers and technicians.

  4. Quality Control: Throughout the project, quality control measures were implemented to ensure the success of the remediation. Real-time monitoring of subsidence levels, crack closure, and the stabilization of the foundations were conducted to validate the effectiveness of the chemical underpinning solution.


Several challenges were encountered during the project:

  1. Coordination: Coordinating the work on multiple properties simultaneously required careful planning and resource allocation to meet the project timeline.

  2. Weather Conditions: Weather fluctuations posed a challenge, as extreme temperatures and rainfall could affect the curing of the injected grout.

  3. Client Communication: Ensuring clear and consistent communication with homeowners was crucial to managing expectations and addressing concerns.


Upon the completion of the project, the following results were achieved:

  1. Subsidence Remediation: The injection works successfully lifted and stabilized the waffle pod foundations, eliminating the subsidence issues.

  2. Crack Closure: Cracks in both interior and exterior walls were significantly reduced in size, enhancing the aesthetic appeal of the houses.

  3. Structural Stability: The properties regained their structural stability, ensuring the safety and comfort of the occupants.

  4. Improved Drainage: Upgraded drainage systems were implemented to mitigate future subsidence risks.


This case study highlights the successful remediation of subsidence issues in five houses built on waffle pod foundations. Through a comprehensive approach that addressed both the structural and drainage problems, the chemical underpinning company was able to restore stability to the properties. Effective project management, careful coordination, and quality control measures played a pivotal role in achieving these positive outcomes. This case study serves as a testament to the importance of addressing the root causes of subsidence and employing innovative solutions to ensure the longevity of structures.
Rectify Group is an Australian ground engineering and asset remediation company.
Enterprise Solutions
Warehouses Mining
Copyright © 2023 Rectify - All Rights Reserved.
Get a Quote