Some residential concrete slabs did suffer damage during the earthquakes, but these were predominantly unreinforced. Although unreinforced slabs were allowed under the Building Code at the time, this is no longer the case. See Building Regulations section below.
Furthermore, the concrete slabs that developed cracks were, in the majority of cases, located in areas previously identified as at risk from liquefaction. The decision to place an unreinforced concrete slab on land with geotechnical problems was unwise.
As a foundation for residential properties, cost effective reinforced concrete slabs will continue to offer outstanding durability, along with low maintenance, fire resistance, thermal comfort and an array of surface finishes. However, design and construction must be fit for purpose and fit for the site on which it is being used.