Seismic and structural strength form the basis of any good building. We can work with you to protect your property – ensuring it's solid, safe and can withstand New Zealand’s unique environmental challenges. 

Prendos professional structural engineers are experienced in the design and strengthening of a wide range of single and multi-storey buildings, and can provide robust solutions for historic and earthquake damaged properties. We can offer advice on a stand-alone basis, or in conjunction with our in-house design team.

Experts in our field, we're renowned for solving the most difficult engineering challenges. Using knowledge gained from the structural remediation of countless buildings, we can provide robust, pragmatic, economic solutions and expert structural advice on building design, renovations and extensions. And if it’s seismic advice you need, our specialist seismic engineers have an in-depth knowledge of earthquake design, and can deliver seismic reports and design solutions to strengthen even the most problematic buildings.

New builds

The 2011 Canterbury earthquakes and the 2016 Kaikoura earthquakes have seen structural engineers adopting new and innovative designs to incorporate the latest seismic resisting systems.

Our structural engineers are have pioneered seismic systems to meet the upgraded risk in Canterbury, simultaneously progressing the profession throughout the country. Our focus is to inform clients of the level of seismic resilience prescribed by the NZ Building Code, and to implement low damage systems that increase this resilience beyond minimum requirements.

What property owners need to know


If you're feeling bewildered by the array of earthquake assessments and reporting, you're not alone. ISA, DSA and %NBS have become part of everyday vocabulary for those in the property and construction industry - and the impact of these changes can be significant and extensive.

The Guidelines for the Seismic Assessment of Existing Buildings, published in July 2017, have been fully revised to take into account the latest technical developments - including lessons learnt from the Canterbury Earthquakes.

One of the requirements is that the Guidelines must be used as the basis for seismic assessments to determine whether or not a building is earthquake-prone. 
Earthquake prone buildings are now defined as being less than 34%NBS (34% New Building Standard), which means the approach to assessments cannot rely solely on ‘judgement’. It also means that Initial Seismic Assessment reports are no longer lightweight exercises without legal implications.


The assessment procedure begins with an Initial Seismic Assessment (ISA), where our experienced structural engineer performs site investigation to provide a qualitative insight on whether a building is potentially earthquake-prone. The ISA report is intended to quickly identify earthquake prone buildings using minimal resources.

A potentially earthquake-prone building (< 34%NBS) may require a Detailed Seismic Assessment (DSA) – containing more detailed calculations and establishing more accurately whether a building is above the 34% threshold.

The analyses are typically carried out based on available existing drawings and building properties from the council, the measurement taken during site investigations, and - if required - concrete scanning to determine the amount of reinforcement in the structures.

The goal of a DSA is to provide a more accurate assessment of the building strength in resisting earthquake. If a building is rated earthquake-prone, we could ‘pinpoint’ the locations of the building that require strengthening through DSA.

After a DSA is completed, we provide a comprehensive report to our client that typically states the summary of the results, the %NBS of the building and the critical member governing this rating, and a seismic retrofit options if required.

At Prendos, we focus on finding the best solution to improve the earthquake resistance of a structure with strong consideration to minimise obstruction and cost.

Seismic strengthening

Once a building owner enters the realms of structural strengthening, the issue becomes how close to %NBS is an appropriate goal.

The Guidelines recommend that all buildings below 34% NBS must be strengthened within different a time window, depending on the hazard the building poses. Therefore, the seismic capacity of a building has now become a crucial consideration for building owners.

We recommend an ISA assessment is carried out when undertaking technical due diligence pre purchase. Having comprehensive knowledge of your building puts you in a more powerful position.

A building that has a high %NBS and grading is a highly marketable investment and conversely understanding a low %NBS and grading can be useful for planning future improvements.

Our structural team have had first-hand experience of the devastating effects of buildings that don’t perform as expected, so we take great responsibility in making sure our work is of the highest standard.

• Construction Reviews
• Feasibility Assessments
• Expert Witness

• Seismic Strengthening Design
• Earthquake/Flood Damage Reports
• S​eismic Assessments (DSA & ISA Reports)

• Structural Peer Reviews
• Legal & Insurance Services
• ETABS Computer Modelling
• Education Design
• Underwriter Reviews
• Risk Assessment & Management
• Concrete Beam Scanning 
• Building Condition Surveys
• Infrastructure Assessments

Our Work.

Rydges Rotorua

Rydges Hotel

Takapuna Grammar School

Honda Case Study


The Nautilus Apartments - Orewa - Prendos

The Nautilus Apartments

Meet with us

If you’d like to talk to us about an existing building, new build project or future property venture, get in touch. We’d love to find out more about your objectives and help you achieve the best possible property solution.

Contact Us.

0800 773 636)

[email protected]

Business Hours.
9am - 5pm

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