Resin injection ground engineering has a number of disadvantages, as we discussed in a previous blog post. 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.
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, it made it even more complicated to stabilize the foundation and minimize subsequent damage.
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 1 year after the resin injection works were completed.
It can be seen from the two surveys taken 1 year apart that the resin injection at this property has in fact and invariably been inadequate and absolutely ineffective. Comparing cracks before and after the resin injection showed that most cracks had worsened. See below:
The injecting company ignored the fact that simply injecting below the footings is not enough to stabilize the foundation if the soil is constantly exposed to moisture.
Ignoring this simple principle that the root of the problem should be found before any engineering action had led to such a disaster.
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 works. 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.