Description: The "Residential Foundation Technical Categories" map first published by the Ministry of Business, Innovation and Employment on 28 October 2011 and updated 5 December 2013.
Technical Category 1 (TC1)
Future land damage from liquefaction is unlikely, and ground settlements are expected to be within normally accepted tolerances. Standard foundations (NZS 3604) are acceptable subject to shallow geotechnical investigation.
Technical Category 2 (TC2)
Minor to moderate land damage from liquefaction is possible in future large earthquakes. Lightweight construction or enhanced foundations are likely to be required such as enhanced concrete raft foundations (ie, stiffer floor slabs that tie the structure together).
Technical Category 3 (TC3)
Moderate to significant land damage from liquefaction is possible in future large earthquakes. Foundation solutions should be based on site-specific geotechnical investigation and specific engineering foundation design.
Technical Category "Not Applicable” have been further assigned to:
• non-residential properties in urban areas
• properties in rural areas or beyond the extent of land damage mapping
• properties in parts of Ports Hill and Banks Peninsula
Copyright Text: Ministry of Business, Innovation & Employment (MBIE)