Technical Land Categories
The main changes that affect repairing and rebuilding houses damaged in the Canterbury earthquakes relate to the land’s Technical Category.
Flat areas of the Canterbury Green Zone are divided into three Technical Categories, or TCs.
These categories provide a guide to the level of site investigation required and the appropriate foundations for the house.
Each property is listed in one of the following:
- TC1 is where future land damage from liquefaction is unlikely. Standard residential foundation assessment and construction is appropriate.
- TC2 is where liquefaction damage is possible in future significant earthquakes. Shallow ground investigations may be required when repairing or replacing foundations. There are foundation repair and rebuild options in the MBIE Guidance.
- TC3 is where liquefaction damage is possible in future large earthquakes. Geotechnical engineering assessment may be required to select the appropriate foundation repair or rebuild.