The owners of a property in Jindabyne, New South Wales, had added a beautifullycrafted stone chimney to an exterior wall of their 4-bedroom brick veneer home.
Since the property is built on weathered granite, which is typically very stable soil, the chimney was installed using a standard footing.
Over time, the footing proved inadequate and the chimney began to subside, pulling the external wall away with it as it leaned. The chimney subsided approximately 20mm, while the wall settlement was approximately 15mm across three lineal metres. The homeowners originally attempted to underpin the chimney with a 700mm deep beam of concrete. This added to the weight on the underlying soil and failed to relieve the pressure, so a new solution was required.
The homeowners wanted to avoid the expense and inconvenience associated with demolishing the chimney, rebuilding the external wall, then rebuilding the chimney.
Mainmark was contracted to consolidate the soil to improve its bearing capacity then re-level and re-support the structure to prevent further subsidence. Mainmark’s proprietary Teretek® deep-lift solution was used to inject engineered structural resin beneath the sunken sections of the building to fill any voids and maximise ground support. The resin then expanded to lift the chimney and wall from deeper in the ground using a controlled force that was constantly monitored electronically with laser levels. The project was completed in a single day, saving the homeowner an estimated $30,000. There was minimal inconvenience to the homeowner and the result is a stable chimney and wall.
This project had three key objectives: to consolidate the soil and improve the ground’s bearing capacity under the footings and beam to prevent further subsidence; to relieve pressure on the external wall; and to re-position and re-level the chimney as much as possible back to its original, vertical alignment.
Doing so, successfully, would prevent further damage to both the building’s façade and the chimney.
Mainmark treated the soil underneath the footings and beam with its proprietary Teretek engineered resin injection solution, using the deep-lift method, which both re-supported and lifted the entire structure.
Acrow Props were initially used to rotate the chimney which helped return it to a nearly vertical position.
Helifix HeliBars were then installed to stitch the cracks in the brickwork and provide further structural integrity along the wall after the resin injection process.
Teretek was specified because it could both improve the foundation ground plus raise and re-level the chimney and wall in a single application. The Teretek resin is injected into the ground at specified points.
When the expanding polyurethane mix enters the ground, the components mix together and expand, filling the voids, strengthening the ground, and also relevelling the above ground structure.
This process meant the cracks in the exterior wall closed up, ensuring any further repair work would be minor when compared to the alternative of complete demolition and rebuilding. Mainmark completed the project in a single day.
Simon Kuner from Kuner Constructions was suitably impressed with the results of the newly re-positioned chimney: “I can’t believe it is as good as plumb now.”
Project Resources & Downloads
Teretek® Re-positions and Re-supports Stone Chimney at Jindabyne Residence
Print At Home Crack Gauge
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Home Avoids Replacement by Using Non-invasive Teretek® Solution
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