Subsidence Ground Stabilisation Overview:
The Restek ground remediation team were busy on a residential property in Cardiff this week. The property was suffering from subsidence due to settlement of soft ground under a one-story extension. Cracks were visible on the interior and exterior of the extension due to the settlement, resulting in the internal doors and windows sticking when being opened and closed.
Restek assessed the subsidence issues through visual site inspection and carrying out a very quick and non intrusive Deep Depth Ground Penetrating survey. We were able to value engineer a resin injection solution to prevent further subsidence of the property. After Restek’s solution was discussed and agreed with the client, a specific grid pattern was designed allowing placement of the injection lances at specified points around the property.
On this particular occasion, the client requested that he lift all the paving slabs up around the extension and then replace them after the resin injection process was completed. Due to the flexible way Restek works, we could accommodate the clients’ request, although most projects we undertake require us to provide a full turnkey package where remediation areas are taken up and replaced after a successful remediation.
Once the injection lances were in position, we covered the extension with protective sheeting and set up a laser level to ensure the stabilisation process for the property didn’t create heave and cause any damage to the property. Our resin injection process is precisely monitored for pressure, movement and volume of materials injected to equal what has been quantified for each area of the scheme. When injecting resins, it is not uncommon to see a small amount of the resin on top of the ground, especially when injecting into soft ground. This resin on top of the ground becomes aerated and resembles a hard foam, whereas beneath the ground, where you have the counter-pressure of the existing ground, the resin doesn’t become aerated and forms a solid mass to stabilise the building.
After each lance was injected with resin, the Restek team tested the drainage system to ensure no blockages had occurred before moving on to the next injection. For optimum performance after each injection, we clean and test the injection equipment. Once the ground stabilisation process is complete, we remove the protruding lances, excess resin and clean away any waste before returning the remediated area as agreed in the project brief.
The client was very happy with Restek’s service and due to the un-intrusive nature of resin injection ground stabilisation, the client and his family did not need to vacate the property at any point during the ground remediation process. The Restek ground stabilisation team used the exact amount of materials as originally quantified and the project was signed off with a manufacturer-backed, 20 year warranty.
How long does it usually take to complete the ground stabilisation process?
Residential ground stabilisation work can often be completed in one to two days and, due to its non-invasive nature, there is usually no need to move out the property before or during the work being carried out. This is entirely dependent on each individual project. Any disturbance of areas around the property during the underpinning process is returned to its original state after any works have been completed, which leaves little to no trace of the work that has been carried out beneath the ground.