Overview
Resin injection ground engineering has a number of disadvantages, as we discussed in the blog post on the pros and cons of resin injection ground engineering.
One of the disadvantages is that it can actually make the problem worse in some cases, rather than improving it. Additionally, this method may not always produce the desired results in terms of differential movements of the house or floor levels.
Project Background
This particular project involved a house that was already significantly damaged and settled. Resin injection at one corner of the house not only failed to improve the overall condition but also made it even more complicated to stabilise the foundation and minimise subsequent damage.
Survey Results Analysis
Below is the brick course survey results conducted by a resin injection company at the house prior to injecting the resin which is compared to a brick course and floor level survey conducted by MFS Engineering approximately one year after the resin injection works were completed.
a resin injection company
MFS Engineering approximately one year after
the resin injection works
It can be seen from the two surveys taken one year apart that the resin injection at this property has, in fact, invariably been inadequate and absolutely ineffective. Comparing cracks before and after the resin injection showed that most cracks had worsened.
When interviewing the homeowner, it was identified that the company who was engaged to carry out the resin injection works advised the owner that the trees located along the side of the house were the most probable culprit for the damage. However, they proceeded with injecting the resin below the footings without conducting any further investigation or consulting with a forensic engineer. They even promised the owner that their resin injection would lift the footings and solve the problem. This lack of proper investigation and reliance on a singular approach contributed to the very unsatisfactory outcome.
Conclusion and Key Takeaways
It is important to note that simply injecting resin below the footings will not prevent further movements if the foundation soil is continually subjected to moisture variations. Therefore, it is crucial to address the root cause of the problem before proceeding with any ground engineering work. In this case, the trees were causing the settlement and removing them or installing a root barrier was the simplest solution to improve the performance of the footings.
Key Points: Lessons from Resin Injection Failure
- Resin injection can worsen existing foundation problems instead of improving them
- Effectiveness of resin injection varies and may not resolve differential movements
- Survey comparisons showed resin injection was inadequate and ineffective in this case
- Addressing the root cause (e.g., tree root management) is crucial before attempting foundation repairs
- Simply injecting resin below footings doesn’t prevent further movements if soil moisture varies
