Technical Category 1 (TC1) – future land damage from liquefaction unlikely. Standard foundations (NZS3604) can be used as long as site meets the ‘good ground’ test
Technical Category 2 (TC2) – damage from liquefaction is possible in future large earthquakes. Shallow geotechnical investigations may be required, depending on damage. Suspended timber floor or enhanced slab foundations outlined in the guidance can be used.
Technical Category 3 (TC3) – damage from liquefaction is possible in future large earthquakes. Deep geotechnical investigation and specific engineering input into foundations may be necessary.