Tebbs Lane is a community housing development based in Gate Pā, Tauranga. The project features 48 one and two-bedroom units across five two-storey apartment blocks. With a site that included tough ground conditions and difficult access, installing deck foundations proved challenging. The StopDigging Groundscrew system provided a smart solution backed by expert support.

Ground conditions around the apartments consisted of relic estuary sediment, with approximately three-quarters of the site overlaid with crushed concrete. This combination of extremely soft ground, and extremely hard crushed concrete made it particularly challenging when it came to laying foundations for the decks and boardwalks. On top of that, the site was very narrow, with no access for large machinery. This made it impossible to pour concrete for the foundations, while concrete piles would have been labour intensive and have added extra weight to the already soft ground. Contractor iLine Construction approached StopDigging to see whether their groundscrew foundation system would be up to the challenge.

StopDigging Groundscrews offer a CodeMark certified solution for residential decking and boardwalk foundations. The system is suitable for most conditions, including soft ground, with on-site testing used to determine pile length required. Installation requires no large machinery, and no extensive groundworks, making the groundscrews a smart option for the challenging site.

At Tebbs Lane, StopDigging conducted initial site testing at various locations on each of the blocks to determine the correct groundscrew for each structure. This project used both deck piles and boardwalk piles — with two different lengths specified to meet the site’s varied ground conditions. The design loads for Boardwalk Piles were specified under Specific Engineering Design by DHC Engineers and then verified as part of the StopDigging system with onsite static pile testing.

The groundscrew foundations were completed in stages, with the StopDigging Bay of Plenty team working in with project timelines, and installing piles for each area as scaffolding was removed from the building. The install team also adapted their drilling and install methods to overcome the challenging and varied ground conditions on site. 

Piling into the crushed concrete covering 75% of the site was especially demanding, and was achieved by first pilot tip drilling, and then installing the groundscrews.

On the flipside, one of the blocks had super soft ground and extremely limited site access, meaning standard machinery couldn’t be used. Instead, the StopDigging team used electric hand drills to complete the 9 decks, averaging 1.5 decks per day. 

In total 372 piles were installed across the project, including both boardwalk and deck piles. The StopDigging team worked in well with contractor iLine Construction, with the groundscrews installed in a fraction of the time of conventional methods, allowing construction timelines to be reduced significantly.

“StopDigging was very flexible and helpful,” comments the iLine Construction team. “They were a team player. They provided engineering services and test piling results to help with the selection of piles, and the system itself was easy to install, with small machinery used to access the site.” 

The project highlights the versatility of the StopDigging ground system — how it can overcome incredibly challenging ground conditions where other foundations aren’t possible, and how the StopDigging team can adapt to on-site challenges to provide a positive outcome.

“The end result is great, and we’d be happy to work with them again.”