Introduction
New Zealand is a seismically active country, with a long history of devastating earthquakes. The 2010-2011 Canterbury earthquakes and the 2016 Kaikoura earthquake are stark reminders of the importance of earthquake strengthening in NZ. As a result, the government has implemented policies to identify and strengthen earthquake-prone buildings, creating a significant growth area for NZ tradies, particularly in Wellington and Christchurch. This guide covers the essential information contractors need to know about earthquake strengthening costs in NZ, including the NBS system, who needs to strengthen, types of seismic assessments, strengthening methods and costs, and opportunities for tradies.
The earthquake strengthening programme is a $10B+ national initiative, with the Ministry of Business, Innovation and Employment (MBIE) and local councils working together to identify and strengthen earthquake-prone buildings. As a contractor, understanding the earthquake strengthening process and costs is crucial to positioning your business for success in this growing market. In this article, we will delve into the details of earthquake strengthening costs, including the costs of different strengthening methods, the cost of seismic assessments, and the opportunities for tradies.
The NBS System Explained
The New Building Standard (NBS) system is a measure of a building's seismic performance, expressed as a percentage of the new building standard. The NBS system is used to determine the seismic vulnerability of a building, with lower percentages indicating a higher risk of damage or collapse in an earthquake. A building with an NBS rating of 34% or less is considered earthquake-prone, while a building with an NBS rating of 67% or more is considered to be at a lower risk of damage. A building that meets the 100% NBS threshold is considered fully code-compliant.
For example, a 1960s Wellington office building with an NBS rating of 22% would be considered earthquake-prone and would require significant strengthening work to meet the 67% NBS threshold. The cost of strengthening this building would depend on the specific strengthening methods used, but could range from $500,000 to $2 million or more, depending on the size of the building and the extent of the work required.
The NBS system is an important tool for building owners and contractors, as it provides a clear measure of a building's seismic performance and helps to identify the level of strengthening work required to meet the 67% NBS threshold. The system is also used by councils to identify earthquake-prone buildings and to prioritize strengthening work in areas of high seismic risk.
Who Needs to Strengthen
Under the Building Act, councils have identified approximately 25,000 buildings that are considered earthquake-prone, with owners having 15-25 years to strengthen these buildings. Priority areas for earthquake strengthening include Wellington, Napier, Gisborne, and Christchurch, where the seismic risk is highest. Building owners in these areas should be aware of the earthquake-prone building policy and take steps to assess and strengthen their buildings as needed.
The earthquake-prone building policy is an important initiative aimed at reducing the risk of damage or collapse in an earthquake. By identifying and strengthening earthquake-prone buildings, we can help to protect people and property, and reduce the economic and social impacts of earthquakes. As a contractor, understanding the earthquake-prone building policy and the NBS system is essential for working in this area.
Types of Seismic Assessment
There are two main types of seismic assessments: Initial Seismic Assessments (ISAs) and Detailed Seismic Assessments (DSAs). An ISA is a desk study that provides an initial assessment of a building's seismic performance, typically costing between $1,500 and $5,000. A DSA is a full engineering review that provides a detailed assessment of a building's seismic performance, typically costing between $8,000 and $50,000 or more, depending on the size and complexity of the building.
Seismic assessments are typically carried out by structural engineers, who have the expertise and experience to evaluate a building's seismic performance. The cost of a seismic assessment will depend on the size and complexity of the building, as well as the level of detail required. Structural engineers typically charge an hourly rate of $150-$250 per hour, depending on their level of experience and expertise.
The following table provides a summary of the costs associated with seismic assessments:
| Type of Assessment | Cost |
|---|---|
| Initial Seismic Assessment (ISA) | $1,500-$5,000 |
| Detailed Seismic Assessment (DSA) | $8,000-$50,000+ |
Strengthening Methods and Costs
There are several strengthening methods that can be used to improve a building's seismic performance, including concrete moment frames, steel bracing, shear walls, base isolation, and unreinforced masonry (URM) strengthening. The cost of each method will depend on the size and complexity of the building, as well as the level of strengthening required.
The following table provides a summary of the costs associated with different strengthening methods:
| Strengthening Method | Cost per m² |
|---|---|
| Concrete moment frames | $800-$2,500 |
| Steel bracing | $500-$1,500 |
| Shear walls | $600-$1,800 |
| Base isolation | $2,000-$5,000 |
| Unreinforced masonry (URM) strengthening | $400-$1,200 |
For example, a 1,000m² building that requires concrete moment frames to meet the 67% NBS threshold could cost between $800,000 and $2.5 million, depending on the complexity of the work and the materials used. Similarly, a 500m² building that requires steel bracing could cost between $250,000 and $750,000.
The cost of strengthening a building will depend on a range of factors, including the size and complexity of the building, the level of strengthening required, and the materials and methods used. As a contractor, it is essential to have a clear understanding of the costs associated with different strengthening methods and to be able to provide accurate estimates to clients.
Real Project Examples
There are many examples of earthquake strengthening projects that have been completed in NZ, including a 3-storey office building in Wellington that was strengthened using concrete moment frames at a cost of $1.2 million. Another example is a heritage building in Christchurch that was strengthened using URM strengthening at a cost of $800,000. A mid-rise building in Auckland was also strengthened using steel bracing at a cost of $1.5 million.
These examples demonstrate the range of costs associated with earthquake strengthening projects and highlight the importance of careful planning and execution to ensure that the work is completed on time and within budget. As a contractor, it is essential to have a clear understanding of the costs and complexities associated with earthquake strengthening projects and to be able to provide accurate estimates to clients.
Demolition vs Strengthen Decision
In some cases, it may be more cost-effective to demolish a building rather than strengthening it. The decision to demolish or strengthen a building will depend on a range of factors, including the age and condition of the building, the level of strengthening required, and the cost of demolition versus strengthening.
As a general rule, if the cost of strengthening a building is more than 50% of the cost of replacing the building, it may be more cost-effective to demolish the building. However, this will depend on a range of factors, including the value of the building, the cost of demolition, and the cost of replacing the building.
The following table provides a summary of the costs associated with demolition versus strengthening:
| Option | Cost |
|---|---|
| Demolition | $50,000-$200,000+ |
| Strengthening | $100,000-$1 million+ |
Opportunities for Tradies
The earthquake strengthening programme is a $10B+ national initiative that presents significant opportunities for tradies, including structural engineers, builders, concreters, steel fabricators, and heritage restoration specialists. As a contractor, positioning your business to take advantage of these opportunities is essential for success in this growing market.
To position your business, you should consider the following:
- Develop a clear understanding of the earthquake strengthening process and the costs associated with different strengthening methods
- Build relationships with building owners, councils, and other stakeholders to identify opportunities for work
- Invest in the necessary skills and equipment to deliver high-quality earthquake strengthening work
- Consider partnering with other contractors or consultants to deliver complex projects
By taking these steps, you can position your business for success in the earthquake strengthening market and take advantage of the significant opportunities available.
FAQ
Here are some frequently asked questions about earthquake strengthening:
- Does my residential home need earthquake strengthening? No, the earthquake-prone building policy only applies to commercial and industrial buildings, not residential homes. However, it is still important to ensure that your home is seismically safe, and you may want to consider consulting with a structural engineer to assess your home's seismic performance.
- Who pays for strengthening - owner or tenant? The cost of strengthening a building is typically borne by the building owner, although this may be passed on to tenants through increased rent.
- Can I do strengthening work without building consent? No, all strengthening work requires building consent, which must be obtained from the local council before work commences.
- How long does strengthening take? The length of time required to complete strengthening work will depend on the complexity of the project, but can range from several weeks to several months or even years.
- Do I need to use a structural engineer for strengthening work? Yes, all strengthening work must be designed and supervised by a structural engineer, who must ensure that the work meets the requirements of the Building Act and the NBS system.
Conclusion
Earthquake strengthening is a critical area of work for NZ tradies, particularly in Wellington and Christchurch. By understanding the NBS system, the types of seismic assessments, and the costs associated with different strengthening methods, contractors can position their businesses for success in this growing market. To learn more about earthquake strengthening costs and to estimate the cost of your next project, visit tradietools.nz/calculators/. This website provides a range of tools and resources to help contractors estimate the cost of earthquake strengthening projects and to position their businesses for success in this market.
As a contractor, it is essential to have a clear understanding of the costs and complexities associated with earthquake strengthening projects. By using the right tools and resources, such as Xero for job management and invoicing, Fergus for project management, and Tradify for quoting and estimating, you can streamline your workflow and improve your profitability. With the right skills, equipment, and software, you can take advantage of the significant opportunities available in the earthquake strengthening market and grow your business.