Why We Chose StopDigging Screw pile Foundations for Pourewa Nursery

A recent ecopod project highlights the benefits of using screw pile foundations for transportable homes in NZ.

Ecopod and StopDigging worked together again for the installation of the Pourewa Nursery Offices, Lunchroom and Composting Toilets in Ōrakei. The project wasn’t without its challenges, but overall it was a success and achieved CCC, ready for the opening of the Native Plant Nursery. They’re now geared up and well on track to achieving their goal to regenerate forests of the Auckland bioregion by raising up to 500,000 native trees each year.

When working with the Tangata Whenua of Ōrakei, Ngati Whatua, screw pile nz foundations were the most appropriate solution for several reasons. As kaitiaki, or guardians, of the land, water conservation, and stewardship was an important design consideration of the plant nursery site. That’s why rainwater is collected into tanks for irrigation (as well as their plant bays collecting rainwater), and we installed composting toilets to reduce water consumption.

The use of continuous composting toilets presented a key challenge in installing the screws, as they had to bridge the excavation for the composting chambers. This was solved with the use of extensions on the screws, as well as stepping the bearers around the compost chambers to maintain the structural integrity of the subfloor.

The StopDigging team is friendly, highly competent, and ensures the best outcomes for foundations are achieved time and again. We have outlined some core processes and benefits of working with StopDigging below:

  1. Fast and simple installation and connection

    • In a matter of a couple of days onsite, the foundations can be designed and installed.
    • In one day, the team are able to do a ground load-bearing capacity test and ground slope calculations to test the required length and quantity of screws required for the job
    • The engineers then check the results and specify the length and quantity of piles appropriate to meet the Code requirements (because of this, no onsite inspection is required until Final).
    • We set out the building footprint with an LBP to ensure correct alignment to the services and driveways as per plans
    • Piles can then be installed by StopDigging for the pods in just one day
    • When it comes to fixing off onto foundations, it’s as easy as bolting a bracket onto the endplate of the screw and bolting or screwing coach bolts into the bearers.
    • The finished height of the screws is generally no less than 400mm off the ground to allow access to fix off
  2. Easily removed if the buildings need to be moved

    • If and when the pods are no longer required in that location, they can easily be unbolted and unscrewed, then screwed in again at the new location.
  3. Lower environmental impact

    • Less excavation is needed, although, with this project, we did scrape the topsoil layer away to bring down the final floor height of the building for wheelchair accessibility.
    • When it comes to being removed, there won’t be any concrete left in the ground
    • Water can infiltrate into the soil to reduce runoff and erosion
  4. A cost-effective and complete engineered solution

    • Working with screw piles nz enables predictable project pricing as they’re costed per pile, so as long as the ground is firm and flat pricing up is easy.
    • Load bearing tests and engineering means the team ensures the minimum screw size and quantity is applied to the foundation.

Overall, eco pod and Ngati Whatua were really satisfied by working together with StopDigging to deliver this project. It’s evidenced in the fact that Ngati Whatua invited them back to install a screw as the base of a 10 metre high pole support to a Carbon Sensor as part of a research project with CarbonWatch NZ.

Screwpiles are a great solution for foundations on relatively flat and firm sites. Alternatives are also possible with eco pods, such as standard timber pile foundations or Surefoot piles which have a higher load rating and can work really well for steep slopes or areas where concrete/rocks/tree roots are prevalent. Get in touch with our team to find out what piling solution might work for your project at sales@ecopod.co.nz.