Challenge
Failed drains washed supporting soils beneath the foundations, causing widespread cracking while a live mains gas supply adjacent to the affected elevation restricted conventional excavation and underpinning methods.
Solution
Geobear injected geopolymer through 13 strategically positioned points, including internal locations beside the gas main, strengthening weakened ground and stabilising the foundations without excavation or disruption.
project duration
Injection locations
Metres treatment depth
Geobear was appointed to stabilise a semi-detached, two-storey property in Co. Dublin after prolonged structural movement caused significant cracking to the left-hand side and rear elevations.
Investigations identified failed drainage as the cause of the subsidence. Water escaping from damaged drains had washed away supporting soils beneath the foundations, resulting in differential settlement and extensive cracking that was visible both internally and externally.
The most severely affected side of the property was located immediately adjacent to the mains gas supply serving both the property and the neighbouring home, creating additional engineering constraints.
The homeowner required a permanent, cost-effective solution that could be completed quickly and with minimal disruption.
Traditional concrete underpinning was considered but rejected due to the extensive excavation, long programme and disruption it would have caused.
The proximity of the live mains gas supply significantly increased the complexity of excavation works, requiring careful consideration of both safety and construction methodology.
The challenge was to stabilise the foundations while avoiding major excavation around the gas infrastructure and allowing the occupants to remain in their home.
Client quote
Attribution
Geobear designed a bespoke geopolymer injection solution based on the site's ground conditions.
A total of 13 injection points were installed to depths of up to 2.1 metres below foundation level. Expanding geopolymer was injected beneath the affected foundations where it filled voids, strengthened weakened soils and restored support to the structure.
Because of the proximity of the mains gas supply, six injection points were installed internally along the left-hand elevation, allowing the foundations to be treated safely without excavation adjacent to the utility.
The entire stabilisation programme was completed in two days, with no excavation, spoil removal or heavy construction equipment.
The property was successfully stabilised while avoiding the disruption and risks associated with traditional underpinning.
Key project outcomes included:
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