Decoding building controls

This Issue This is a part of the Building controls feature

By and - , Build 161

New Zealand’s building controls framework can appear complex, but it has a simple objective at its core – to ensure buildings are safe and fit for purpose.

Hierarchy of New Zealand building controls. (Adapted from MBIE drawing.)

NEW ZEALAND’S SYSTEM for building controls is set out in legislation and regulations that determine how building work can be done and who can do it and ensures that checks and balances are in place.

The building control system is performance-based. This means the focus of the system is on how a building must perform in its intended use rather than describing how it must be designed and constructed.

In practice, there are many ways of meeting the performance requirements. The advantage of a performance-based Building Code is the flexibility it allows for development and innovation in building design, technology and systems.

Building controls framework

The three core elements of the New Zealand framework for building controls are:

  • the Building Act 2004
  • building regulations
  • the Building Code.
Hierarchy of New Zealand building controls. (Adapted from MBIE drawing.)

Building Act 2004

The Building Act governs the building sector in New Zealand. It sets the rules for construction, alteration, demolition and maintenance of new and existing buildings, including the process for building consents.

The purpose of the Building Act is to ensure:

  • people can use buildings safely and without endangering their health
  • buildings have attributes that contribute appropriately to the health, physical independence and wellbeing of people who use them
  • people who use a building can escape from the building if it is on fire
  • buildings are designed, constructed and able to be used in ways that promote sustainable development.

Other laws also apply to building projects. These include those relating to health and safety, council bylaws, the Resource Management Act 1991 (resource consents) and laws specifying that certain plumbing, gas and electrical work must be carried out by qualified professionals.

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Building regulations

Several building regulations sit under the Building Act and provide details of particular building controls. Examples include prescribed forms, lists of specified systems, definitions of ‘change of use’ and ‘moderate earthquake’ and rates for levies and fees.

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Building Code

The Building Act requires that all building work must comply with the Building Code. It sets the minimum performance criteria that all building work must meet, even if the work does not require building consent.

Technically part of a building regulation (contained within Schedule 1 of the Building Regulations 1992), the Building Code covers structural stability, access, moisture control, durability, services and facilities, and energy efficiency.

Pathways to Building Code compliance

In processing a building consent, a building consent authority – usually the local council – must assess the plans and specifications to ensure the proposed work complies with the Building Code. A Code Compliance Certificate is issued once the building work is finished and the building consent authority is satisfied the work complies with the building consent.

As it is performance-based, there is more than one way to comply with the requirements of the Building Code. To demonstrate compliance with the Building Code, building owners may choose one of two routes:

  • Deemed-to-comply route
  • Alternative method route.

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Deemed-to-comply route

Designs that follow an Acceptable Solution, a Verification Method, a positive determination or use a CodeMark certified building product in accordance with the use and limitations defined on the certificate are deemed to comply with the Building Code. They must be accepted by the building consent authority as demonstrating compliance with the Building Code.

Acceptable Solutions and Verification Methods are published and maintained by the Ministry of Business, Innovation and Employment (MBIE).

Each Acceptable Solution and Verification Method provides practical information on one way to meet the performance requirements of Building Code. There is at least one Acceptable Solution for each clause of the Building Code.

Acceptable Solutions provide a prescriptive design and construction process as a means to meet the performance requirements of the Building Code. They give specific construction details, often for commonly used building materials, systems and methods, and include step-by-step instructions for building methods.

Verification Methods provide a series of tests or calculation methods that provide one way to meet the performance requirements of the Building Code. Verification Methods can include:

  • calculation methods (recognised analytical methods and mathematical models)
  • laboratory tests (for prototype components and systems)
  • tests in situ (which may involve examination of plans and verification by test, where compliance with specified numbers, dimensions or locations is required).

Acceptable Solutions and Verification Methods may list New Zealand standards (called cited standards) that form part of the means to comply with the Building Code. For example, NZS 3604:2011 Timber-framed buildings is cited in Acceptable Solution E2/AS1 as a means to comply with the requirements of Building Code clause E2 External moisture but only for the clauses referenced in E2/AS1.

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Alternative method route

Not all building work is covered by an Acceptable Solution or Verification Method, or there may be a desire to deviate from an Acceptable Solution or Verification Method in some way. In these cases, an alternative method that demonstrates compliance directly with the Building Code performance criteria is required.

Alternative methods can relate to a material, component or construction method and may range from minor variations to an Acceptable Solution or Verification Method to radically different design and construction approaches. Paths to compliance for alternative methods are detailed in Supporting alternative methods (see pages 50–52).

An alternative method usually requires specific design and input from suitably qualified people, such as architects or engineers.

Once accepted as Code compliant by the building consent authority, it becomes an Alternative Solution.

Want to know more?

MBIE’s Building Performance website provides guidance on all aspects of the building process and the building control system.

The New Zealand Building Code Handbook provides a full explanation of the provisions of the Building Code and how these relate to other aspects of the building control system.

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For more

Further information on the building control system and a downloadable copy of the New Zealand Building Code Handbook are available on MBIE’s Building Performance website at www.building.govt.nz.

 

BRANZ’s Building Basics Building Code Compliance is also useful. See the BRANZ Shop at www.branz.co.nz/shop.

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More articles about these topics

Articles are correct at the time of publication but may have since become outdated.

Hierarchy of New Zealand building controls. (Adapted from MBIE drawing.)

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