When a Macclesfield homeowner purchased his brick two-storey house, he intended to renovate the property. The house, which was approximately 12 years old, had been constructed on a mix of sandy clay and made/filled ground, which may not have been compacted adequately, leading to subsidence. Furthermore, the site was sloping, leading to uneven subsidence by as much as 82mm in the lowest position.
The average subsidence was approximately 41mm. As a result of the subsidence, the home was unstable. Internal doors would swing of their own accord and, if left untreated, the home may have become structurally unstable. To prepare the house for occupancy, the homeowner needed to address the subsidence before commencing any other renovations. The homeowner considered a variety of options, including invasive traditional underpinning that would have only stabilised, but not lifted and re-levelled, the home. With a tight timeframe due to other renovation works, the homeowner contracted Mainmark to re-level and re-support the building. Mainmark recommended its JOG Computer-Controlled Grouting method to re-level and strengthen the ground underneath the entire home. Mainmark was given a five-day window to complete the project. Access to the house was via a shared driveway that was narrow and sloping. Mainmark worked closely with the neighbours to devise a plan of works that would minimise disruption to them. The Mainmark team configured all the equipment within a small lorry that could fit down the narrow laneway, then used the lorry as a work platform to make the most of the limited space available. As there was no access for large vehicles, Mainmark transferred deliveries from outside the gated community to the project site via a forklift. Mainmark’s JOG method was the least disruptive option available to the homeowner because it did not require any structural demolition, removal or reinstatement of landscaping, or interference with floor slabs. Mainmark lifted the 64m2 home by as much as 82mm and achieved a maximum differential of just 6mm across the entire area of the house. Some new buildings are constructed with greater differentials than this, so Mainmark’s ability to attain such precision, and complete the job in five days, was an exceptional outcome.
Mainmark was required to lift the home’s foundation and floor slab by as much as 82mm in its lowest position and to strengthen the underlying ground to minimise further subsidence.
The entire 64m2 structure needed to be lifted in a controlled and precise manner. Work had to be carried out with limited site access, due to a narrow and sloping shared driveway. Technicians were required to consult with the homeowner’s neighbours to minimise disruption to their routines. Due to the homeowner’s renovation plans, Mainmark was tasked to complete the project within a tight fiveday timeframe.
The homeowner had considered invasive approaches such as traditional underpinning. However, the logistics, cost, and disruption associated with those approaches made them unviable for this project. The homeowner sought a solution that would be both cost-effective and non-invasive, resulting in minimal disruption.
Mainmark therefore recommended its JOG Computer-Controlled Grouting. The computercontrolled cement grout injection provides an extremely precise method for stabilising soils, consolidating weak ground, and lifting foundations to deliver specific, engineered outcomes. Compared to alternatives, the JOG approach is more reliable and less invasive. The application process operates under computer monitoring for exceptional accuracy. It places minimal stress on separate sections of the structure because all parts are supported and lifted together using small, sequenced injections of high-mobility fast-setting cementitious grout. The cementitious grout also fills voids and fissures, and binds the underlying soil together to form a stronger, more stable foundation. The Mainmark team completed the project in less than five days; arriving on-site on a Monday morning, completing the project, including cleaning up, and leaving the site by lunchtime on the Friday. Eddie Connor, the homeowner, said, “I’m very happy with the results; they exceeded my expectations. We have now added a small extension at the rear of the property where we had the largest amount of settlement. The ground conditions are mainly sand and we had no problem getting these foundations passed by Building Control. I’d be more than happy to recommend Mainmark to anyone requiring their building to be re-levelled.”
Teretek® Resin Injection Used to Underpin Subsiding London Property
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