Earthquake Engineering in New Zealand: Strengthening for Safety and Compliance

New Zealand’s seismic risk is among the highest in the world, and the regulatory framework reflects that reality. At DEG Consulting Engineering, our Earthquake Engineering team provides practical, standards-aligned solutions to help builders, asset owners, and councils meet their obligations under the Building Act 2004 and the Building (Earthquake-prone Buildings) Amendment Act 2016.

From seismic assessments to retrofit design, our work supports safer buildings and more resilient communities.

Seismic Assessments: ISA and DSA

Seismic assessments are the foundation of earthquake risk management. DEG offers both:

These assessments follow the Engineering Assessment Guidelines issued by MBIE and are required by councils to determine whether a building is earthquake-prone under Subpart 6A of the Building Act.

Retrofit Solutions: Base Isolation and Strengthening

DEG provides tailored retrofit solutions, including:

• Base Isolation Systems: Originally developed in Wellington, base isolation involves installing flexible bearings between the foundation and superstructure to reduce seismic energy transfer. It is a proven low-damage solution for civic, commercial, and increasingly residential buildings.
• Strengthening of Historic and URM Buildings: Unreinforced masonry (URM) buildings are common across New Zealand and pose significant life safety risks in earthquakes. DEG applies practical strengthening methods—such as diaphragm anchoring, parapet bracing, and cavity wall ties—to improve seismic performance while respecting heritage value.

We understand the financial and technical challenges faced by owners of older buildings, particularly in regional centres. Our team works to deliver cost-effective, code-compliant solutions that meet both safety and heritage requirements.

Legal Framework: Building (Earthquake-prone Buildings) Amendment Act 2016

The Amendment Act, in force since 1 July 2017, introduced a national system for managing earthquake-prone buildings. Key provisions include:

• Buildings rated below 34% NBS are deemed earthquake-prone
• Timeframes for assessment and strengthening vary by seismic risk zone (high, medium, low)
• Councils issue EPB notices and maintain a public register
• Owners must strengthen or demolish within set timeframes, or face enforcement action

DEG ensures all assessments and retrofit designs comply with MBIE’s EPB methodology and the NZ Building Code (Clause B1 – Structure).

Supporting Builders and Construction Firms

We work closely with builders and contractors to:

• Provide seismic design input for new builds and alterations
• Deliver ISA/DSA reports for consent and insurance purposes
• Support CCC applications with PS1 and PS4 documentation
• Offer practical advice on strengthening options and sequencing

Our goal is to make seismic compliance achievable, defensible, and aligned with construction realities.