A home in Melbourne, built on a former landfill site, had experienced significant subsidence due to loose clay soil underneath, resulting in unlevel floors.
The property had a string of trees planted at the front of the block, which contributed significantly to the subsidence. Consequently, most of the drop was at the front of the home and graduated towards the back of the property.
Mainmark applied Teretek® engineered resin and JOG Computer-Controlled Grouting to raise the house back to as close as possible to its original levels. This solution was ideal given the home was located on dry, silty clay. Mainmark was able to successfully lift the home by 132mm across the front of the house, bringing it back to level.
Mainmark’s unique approach was fast, cost effective and non-invasive. Despite space restrictions on site, the complex project was completed in just six days.
The front of the house needed to be raised more than 100mm across a 5m grid on the ground floor slab.
It was also important that the home’s occupants were not unduely inconvenienced throughout the project and that there was no future risk of damage to the home as a result of the lifting procedure.
There was also restricted access on the small suburban residential block, requiring the site compound to be established on the driveway of the home.
The house construction was rigid with several concrete beams across the floor, in what’s known as a raft slab, which enabled Mainmark to complete most of the lifting using its award-winning JOG Computer-Controlled Grouting. The strong structural integrity of the house made the JOG approach ideal, as the entire structure could be lifted at once without damaging the slab.
To complement the works, Mainmark used Teretek® engineered resin injection solution to further strengthen the home’s structural integrity by filling voids and strengthening the ground during the lifting process, thereby supporting the home to ease any structural stress.
This was the first time this combined process was used in Australia on a residential property.
Mainmark’s JOG solution uses computer levelling technology to inject a variable mobility cementitious grout sequentially through a series of injection ports, of up to 40mm in diameter, drilled into the floor slab. The grout pressure and flow are tightly controlled using the JOG computer system.
As the structure began to rise, Mainmark used its proprietary Teretek® engineered resin injection solution to fill the voids in the centre of the slab, which occurred as the lifting took place. The resin was
delivered through a series of very small injection ports of just 16 mm in diameter. This resulted in very little disruption to the home.
The original target was to achieve a lift of 91mm, however Mainmark was able to exceed this and lifted the structure more than 100mm: 63mm of this lift occurred in just a single day. The lift happened simultaneously across the entire structure to limit potential damage and gently ‘floated’ the house back
Mainmark’s resin and cementitious grout solutions are lightweight, so they didn’t impose extra weight on the existing weak ground. Likened to ‘keyhole surgery’ and using non-invasive equipment, no excavation was required, so costs were contained.
Mainmark overcame site access limitations by positioning equipment, that would not fit, on the driveway.
The light, rigid construction of the house, combined with favourable onsite ground conditions, resulted in a fast and controllable lift across the designated area to bring the home back to level in a short timeframe with minimal disruption.
Project Resources & Downloads
JOG and Teretek® Used to Re-level a Two-storey House
JOG Computer Controlled Grouting
Download filePlease fill out this form to access this file.
Teretek® Helps West Australian Homeowner Avoid Having to Replace Wall
© 2023 The Mainmark group of companies. ‘Mainmark®’, ‘Terefil®’, ‘Terefirm®’ and ‘Teretek®’ are trademarks of the Mainmark group of companies.
Mainmark Ground Engineering Pty Ltd
ABN: 51 606 182 503