Description

The STOPDIGGING! Ground Screw Foundation System is an alternative to piles and foundation walls (as defined in NZS 3604:2011) using a pre-engineered solution for buildings within the scope of NZS3604:2011 or NASH Standard Part 2: May 2019 and meeting certain ground conditions or for use in buildings outside that scope or with other ground conditions by specific engineering design.

The STOPDIGGING! Ground Screw Foundation System comprises ground screws matched to site conditions by static pile testing to determine the screw type, size and depth for installation to achieve the capacity required to meet the design loads.

The STOPDIGGING! Ground Screws are circular hollow sections with a continuously welded helix manufactured from steel that complies with ISO 630 FE360A (High Tensile Steel for Structural Purposes). The ground screws are coated with a hot-dipped galvanised coating that achieve an average of 125 µm zinc cover.

The STOPDIGGING! Ground Screw Foundation System comprises the following STOPDIGGING! components:

• Ground screws: SGU Diameter 67mm and SGC Diameter 76mm, 89mm, 114 mm (lengths to suit design load requirements)
• Brackets: SGL and SGE

Scope

1. The STOPDIGGING! Ground Screw Foundation System is certified for use as foundations of buildings, located in Exposure zones B, C and D (as defined in NZS3604:2011 section 4.2,except microclimates), as described in either 1(a) or 1(b).

• a. foundations of buildings, new and existing, with suspended floors that come within the scope of NZS3604:2011 section 1.1.2 (b to o) or NASH Standard Part 2: May 2019 section 1.1.3 where;
  
  • i. the foundations are situated on ground with adequate bearing capacity as established by static pile testing (but excluding ground that has the potential for liquefaction or lateral spread); and
  • ii. diagonal bracing is not required; and
  • iii. the maximum floor live load does not exceed 3kPa; and
  • iv. the maximum above ground height of the ground screw does not exceed 900 mm; and
  • v. the spacing between joists and bearers is within the scope of Table 3 or Table 4, Appendix 2 of the STOPDIGGING! Design Guide Version 6.1, June 2024 (“the Design Guide”);
• b. foundations for buildings not within the scope of 1 (a), where:
  
  • i. the foundations are situated on ground with adequate bearing capacity as established by static pile testing, but the ground has the potential for liquefaction or lateral spread; or
  • ii. diagonal bracing is required; or
  • iii. the maximum floor live load exceeds 3kPa; or
  • iv. the maximum above ground height of the ground screw exceeds 900 mm; or
  • v. the spacing between joists and bearers is not within the scope of Table 3 or Table 4, Appendix 2 of the Design Guide.

2. The STOPDIGGING! Ground Screw Foundation System shall be designed in accordance with the relevant section of the STOPDIGGING! Design Guide and installed in accordance with the STOPDIGGING Installation Guide Version 4.0, March 2024.

3. For foundations under 1(a) the LBP Designer shall complete Part 1 of the STOPDIGGING! Ground Screw Foundation System Design Declaration Version 2.2, June 2024 to certify that the foundation system has been designed in accordance with the pre-engineered solution described in the Design Guide, Part 1.

4. For foundations under 1(b) a CPEng (Structural or Geotechnical) shall complete Part 2 of the STOPDIGGING! Ground Screw Foundation System Design Declaration Version 2.2, June 2024 to certify that the foundation system as a specifically engineered solution in accordance with the Design Guide, Part 2.

5. The installer shall provide a complete STOPDIGGING! Installation Record Version 1.0, September 2022 and STOPDIGGING! Static Pile Test Report Version 1.0, February 2023 for submission with an application for a Code Compliance Certificate that all installation conditions of this CodeMark certificate have been met when installing the STOPDIGGING! Ground Screw Foundation System.