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Your Easy Guide to New Zealand Building Code
- Bill Zhao
- Aug 23
- 15 min read
Navigating the sea of codes and conditions set by New Zealand’s current building code can seem quite daunting, but a robust sorting scheme and an abundance of online resources make it easier than ever to venture through. The building code defines the minimum performance standards that buildings must meet, and is enforced with the purpose of creating safe and durable homes that prioritise the health of their users. Governing the building code is Building Act 2004, which sits atop the legislation hierarchy. While the purpose of the Building Act is to establish the legal framework for building work, the building code sets out the specifics of performance standards.
One of the most notable clauses to remember of the Building Act is that all building work is to comply with the building code, regardless of whether a building consent is required.
The current New Zealand building code is divided into 8 main clauses, from A through H. These cover the following:
Multi-clause Elements
It is important to note that even single parts of a building can come under multiple sections of the building code. Windows and doors, for example, have many different functional requirements demanded across numerous clauses. B1 may call for its structure to be able to withstand a certain amount of impact, while E2 will ask for how resilient it is against water ingress.
A: General provisions
Section A differs from the rest of the clauses as it primarily acts in more of an administrative capacity: defining building categories, clarifying terminology definitions, and dictating importance levels.
A1: Classified uses
The purpose of this section is to define specific categories for all building types in New Zealand to fall under. Seven categories currently exist: housing, communal residential, communal non-residential, commercial, industrial, outbuildings, and ancillary. This is important as it allows specific rules and conditions to be assigned for buildings under a particular category.
A2: Interpretation
This clause is written with the intent of providing a common definition for regularly used terms so that readers can extract the same meaning that the regulating bodies intended. Essentially, it is a detailed glossary of common words and phrases used in the industry, aimed at setting a common meaning for each entry. When such terms are used during a project, their definition is to refer to this section.
A3: Building importance levels
Section A3 is aimed at assessing the level of consequence if a building is to fail – whether through loss of structural integrity, posing a threat to human life, or otherwise being incapable of performing its most basic and critical functions. The level of consequence is defined into five “importance levels”, with level 1 being of the lowest impact to societal function, and level 5 being the highest. Examples include sheds for level 1, typical homes for level 2, schools for level 3, hospitals for level 4, and major dams for level 5. The greater the importance level, the larger a risk it poses to the population.
B: Stability
Section B details components that affect the structural integrity of buildings and elements that affect its load bearing capacity. This extends to the materials used – of which there are stringent durability requirements, aimed at making homes safer for longer.
B1: Structure
In withstanding loads, traffic, and weather, buildings must be resilient enough to carry out their core functions. Clause B1 of the building code tackles the combination of loads that a building, its elements, and its sitework are likely to encounter during its lifetime. It promotes awareness of a wide range of factors that can affect building health, including everything from temperature changes to explosions. Building practitioners are taught to assess the likely conditions that their building may face and plan accordingly. The common home may not encounter explosions in its lifetime, but this changes as the type of building changes. Industrial buildings, for example, have a higher likelihood, and therefore such an event is to be prepared for more diligently.
B2: Durability
The functional requirement of B2 is to ensure that the building can satisfy the other functional requirements of the code throughout its lifetime. This encompasses the building materials and components used, as well as the methods of construction. In achieving this goal, building practitioners are assigned the aim of making the building long-lasting through the use of materials and methods that are suited for prolonged use so that it continues to meet the requirements of the building code with only normal maintenance.
C: Protection from fire
Section C encompasses everything fire-related – from prevention methods to containment, as well as contingencies if it spreads. It also concerns broader fire solutions such as accessibility for firefighters and nearby water sources.
C1: Objectives
As section C contains 6 total clauses, C1 aims to define the goals of the remaining 5. Similar to section A, it acts as more of an administrative clause to provide further context for following ones. C1 in particular outlines the following objectives:
(a) safeguard people from an unacceptable risk of injury or illness caused by fire,(b) protect other property from damage caused by fire, and
(c) facilitate firefighting and rescue operations.
C2: Prevention of fire occurring
True to its namesake, clause C2 is tasked with educating building practitioners on minimising the risk of fire during the use and installation of fixed appliances and equipment.
C3: Fire affecting areas beyond the source
We all know how quickly fire can spread, and how much of a danger it poses to families and homes. The consequences of which can be broadly seen in the news and media. Spreading fire is a common trope in films – and for good reason. The threat it poses is genuine and not to be underestimated. Clause C3 calls for design and construction that minimises the risk of injury to people who are not close in proximity to the fire source. This extends to the upper floors and other properties, to ensure that they are protected from fire spread. The elements of importance include the building materials for walls and ceilings, as well as their positioning, which affects the way in which fire may spread. C3 also defines rules on how much fire is allowed to spread, either horizontally, vertically, or externally.
C4: Movement to a place of safety
Clause C4 talks about the ease of which it is to escape from a fire – which isn’t limited to just the doors and halls. This also applies to warning systems such as alarms and detectors, but also visual aids in determining escape routes, such as backlit fire exit signs and direction signage. It also sets conditions for route visibility in the case of smoke. Fire sprinkles are also covered by this clause.
C5: Access and safety for firefighting operations
When dealing with a fire, having help is critical to maximising safety and preventing further damage. Clause C5 discerns the accessibility levels for firefighters and rescue operations to perform their duties in the case of fire emergency. This clause covers accessible water sources in proximity, such as sprinkler or fire hydrant systems. With water being essential to firefighting operations, accessible delivery can prove invaluable.
C6: Structural stability
A common trope found in movies and TV is when characters fall victim to a falling beam inside a burning house, trapping them in place at the mercy of fire and smoke. While it may seem like a convenient way to raise the stakes, the consequences of this in reality are unquestionably dire. Clause C6 tackles the stability of these very beams. However, “conveniently weak” they might be in media, the NZ building code encourages practitioners to apply structurally sound designs and materials so that structural stability can be maintained for longer in the event of fire. A notable aspect of this clause is protecting elements that are more vulnerable to fire in the case that their failure leads to the collapse of an element that has greater fire resistance – which otherwise would not have failed.
D: Access
This section primarily deals with the ease in which people can enter and exit buildings. Stairs are a particular focus of this section, as well as accessibility accommodations.
D1: Access routes
Section D1 oversees requirements for building accessibility, especially concerning the main entrance of a building, but also corridors, doors, stairs, ramps, and lifts. The purpose of this clause is to ensure that people can safely move into, within, and out of buildings. Safety during this operation is paramount, as measures such as anti-slip features, stair treads, and handrails are also covered. Accessibility measures are also included, such as the requirement for accessible routes to accommodate both a wheelchair-bound person and a walking person to pass at the same time.
D2: Mechanical installations for access
D2 is a clause that typically applies to larger buildings as it covers installations such as lifts or escalators. This clause talks about the safety requirements of such installations, which involve load thresholds, injury-avoidant design, and safety in the case of emergency. Typical residences may also encounter this clause when installing mobility/accessibility features such as stairlifts and platform lifts. The purpose of this clause is to ensure the safety of its users while carrying out its designed purpose, whether it’s preventing excessive acceleration, making moving parts inaccessible, or having a proper failsafe mechanism.
E: Moisture
Many of you may remember the leaky homes crisis New Zealand faced – the consequences of which have contributed to the very Building Act that dictates our current rules and procedures. The crisis was largely in part due to the buildings’ vulnerability to water ingress, which led to mould and structural vulnerabilities. Section E is aimed at preventing such issues from occurring, as well as a broader range of water-related implications.
E1: Surface Water
Clause E1 dictates the prevention of rainwater and other surface water variants from entering the building and harming people. E1 primarily concerns the redirection of surface water for the purpose of safety. This is done via gutters and downpipe for rain, into drainage systems, where surface water is disposed of using gravity.
E2: External moisture
This focuses on keeping buildings resilient to the penetration and accumulation of moisture from the outside and ensuring there is no moisture penetration into the building envelope (the components that separate the outside from inside). The primary building elements that this concerns are the walls, floors, and structural elements that have the potential to come into contact with external moisture. It asks for such building elements to remain functional and without permanent damage after moisture dissipation.
E3: Internal moisture
The building code’s clause on internal moisture focuses on making safe indoor areas that are vulnerable to, or are expected to come into water. This section demands an adequate amount of thermal resistance, ventilation, and space temperature to habitable spaces and places with moisture-generation potential such as bathroom and laundries. The goal of this clause is to safeguard people by minimising the likelihood of fungal growth and damage to buildings due to moisture. Elements commonly associated with this clause include bathroom surfaces, sanitary fixtures, and elements that are expected to come into contact with water, such as sinks, tubs, and showers.
F: Safety of users
Safety of users clocks in as the second-longest section of the building code, in terms of clauses – but with good reason. After all, the legislative texts all champion safety as the paramount goal amidst all its purposes. Section F includes all that concerns safety, with many building elements expected to reprise their roles in this section, so long as they have something to do with the wellbeing of users. For the sake of brevity, some clauses have been merged into a single theme for this article.
F1-F3: Hazardous agents, materials, and substances
Clauses F1 to F3 all concern the presence of hazardous items. The culmination of these can be summed up as the presence of physical or chemical items that pose a threat to human wellbeing. The objective of these three clauses is to protect people from injury caused by a hazardous presence. For example, F1 may include mould, sewage, or contaminated soil. F2 may include asbestos, toxic paint, and transparent panels that are deemed too inconspicuous to notice on an otherwise unimpeded path of travel. F3 encompasses items such as gas cylinders, flammable liquids, and chemical containers.
F4: Safety from falling
Clause F4 covers instances where people can fall 1 metre or more, and is primarily used in concern with stairs, roof access, and ramp fixtures. The purpose of this clause is to prevent accidental falls by making sure appropriate safety measures are in place for the relevant fixtures. This include making sure fixtures and barriers are of an appropriate rigidity, that they are strongly affixed, and that people of varying heights and sizes can use them to effect.
F5: Construction and demolition hazards
This clause primarily concerns zones of work – either being actively worked on or otherwise. Written with the aim of preventing accidents and injury due to construction and demolition work, F5 encompasses hazards such as dangerous objects, improper site cordoning, and overreaching construction elements. This is to ensure that passersby cannot endanger themselves and that site workers aren’t in dangers of being an unsuspecting victim to a falling tape measure. Signage, barriers, and entry restriction are involved to stop unauthorised entry, and that only approved personnel can enter.
F6-F8: Alert and assistance in escape and emergency
These three clauses all concern warning and accessibility systems in case of emergencies and hazards. F6 deals with escape route visibility in the case of main lighting failure and applies to specific risk groups and areas in buildings. This primarily involves backup emergency lighting, and the required levels of which are dictated in the building code. F7 deals with warning systems and most commonly involve fire alarms, but are not limited to such. Emergencies such as chemical leakage, equipment failure, and temperature change can also be linked to alarms, which are required to warn the people in the affected area. This is done for safety, and swiftness of response action.
F9: Restricting access to residential pools
A more recent clause, F9 discusses the requirements of barriers and enclosures around pools. While safety in general is important for this clause, the spotlight is shone on unsupervised children in particular. An unrestricted pool can pose significant hazards for young children, who are naturally curious about the water. This clause aims to reduce accidents involving young children by implementing barriers and gates around residential pools.
G: Services and facilities
The section with the largest amount of building code clauses, Section G serves to address in-home fixtures, ranging from food preparation facilities, to lighting, to gas and water, as well as everything in between.
G1: Personal hygiene
The goal of this clause is to ward people from illness caused by infection or contamination. The building code outlines the means of doing this as through an appropriate number of places used for personal hygiene and for the facilities to be placed in convenient locations. Chiefly among the facilities would be your kitchen and bathroom sink, which are used for washing and cleaning. This clause ensures that buildings have an appropriate amount of them, and in appropriate places relative to their purpose.
G2: Laundering
Similar to personal hygiene, the laundering clause calls for buildings to have adequate space and facilities for performing laundry duties. This applies to locations where laundering is commonplace, such as residential homes, aged care facilities, childhood centres, and camp grounds. Relevant items likely include washing machines, racks, and drying fixtures. Also similar to G1 is the accommodation for disabled people to use such facilities.
G3: Food preparation and prevention of contamination
Perhaps most relevant to those of you performing kitchen renovations, clause G3 is important in guaranteeing you space for chilled storage, food preparation, and utensil washing. One notable aspect of G3 is that interior linings and work surfaces “shall be impervious”, which refers to surfaces that resist absorption, prevent microbial growth, and are durable enough to withstand regular cleaning. This results in kitchen surfaces that can resist splashes and minimise bacteria growth. Similarly to G1, this clause is also written with the aim to safeguard people from contamination.
G4-G5: HVAC (Heating, Ventilation, and Air Conditioning)
Largely referring to ventilation (but also air filtration and condition to an extent), clause G4 is instrumental in ensuring fresh air for homeowners. It dictates that such systems are to be constructed and maintained in a way that prevents the multiplication of harmful bacteria within them. Outside of the aforementioned systems, the kitchen rangehood is also covered, as it deals with cooking fumes. Industrial buildings may also have specialised systems that deal with chemicals and other gases. G5 is aimed at the “H” of HVAC, with the goal of safeguarding people from low air temperature, inadequate activity space, and unsafe installations. G5 mostly concerns the heating systems and free space of a home, aimed at providing adequate heating so that people don’t get ill from a cold home, while also making sure that a building isn’t constructed without ample space for activities. Air conditioners, heaters, and building layout are G5’s primary concerns.
G6: Airborne and impact sound
More likely than not, you’ve heard raucous shindigs and incoherent ramblings from homes that aren’t your own, or perhaps you’ve seen content creators with acoustic panels splayed across their walls. The composition of a building and its interiors - particularly its walls, have much to do with noise suppression and dampening. While slapping a decorative panel on your wall won’t come under G6, building elements such as insulation, cladding, and plasterboard most certainly do. This clause is aimed at curbing undue noise transmission between buildings, and products such as GIB’s Noiseline are aimed at fulfilling that purpose.
G7-G8: Natural and Artificial Light
Sunlight is deemed by many as one of nature’s greatest remedies, and the New Zealand building code certainly seems to agree. The aim of G7 is to safeguard people from “loss of amenity” due to a lack of natural light. While many may go out of their way to avoid it, natural light is nonetheless important for both health and home lighting. This affects windows, skylights, and to a lesser extent, sun tunnels. In a similar vein, G8’s goal is to ensure adequate lighting as a whole, so that objects are visible and movement is safe. This includes your lightbulbs, table lamps, and accent lights.
G9: Electricity
With how undeniably prevalent electricity is in our lifestyles, the amount of power draw that people demand has increased dramatically. Clause G9 is aimed at ensuring the safety of electrical systems, especially in the sense of having safeguards against fire and injury. Naturally, the wingspan of this clause’s coverage is immense: ranging from power outlets, to wiring, to circuit breakers and many more. Excessive temperatures are also listed in the clause, with the aim of safeguarding users from exposure to hot components.
G10: Piped services
While most use cases for this clause will relate to water and gas, industrial buildings may supply other forms of fluid via pipes. Clause G10 aims to ward people from illness cause by extreme temperatures or hazardous substances supplied by the pipes. This also extends to the pipes’ integrity and durability, as well as the placement and proximity to electrical systems or locations that could otherwise cause hazards. Fixtures affected by this clause include the pipes themselves, pipe positioning, and pipe accommodations around the home.
G11: Gas as an energy source
Using gas as an energy source comes with its own risks, such as the potential for fire and explosion. The aim of G11 is to prevent injury from gas as energy sources but also to ensure that sufficient gas is provided thanks to proper installation and ventilation. This affects gas supply systems, gas appliances, and ventilation systems.
G12-G14: Water supplies, foul water, and industrial liquid waste
G12 dictates the need for buildings to have water outlets and sanitary fixtures that can supply both safe and adequate water. It is targeted at curbing leaks, injuries, scalding, and illness. It ensures potable water for drinking, food prep, washing, and hygiene and is targeted towards the plumbing and hot water systems. In the same vein, G13 discusses foul water, and is aimed at the safe separation between contaminated water and potable water. It also seeks to guard against the odours of wastewater and waste accumulation. This also relates to the plumbing system, as well as the toilets and pipes. Similar to G13, G14 deals with liquid waste on an industrial level, tackling woes such as blockages, gas entrance, leakages, and foul air. The requirements are generally scaled up for industrial buildings and it discusses requirements such as adequate capacity for waste volume, as well as vehicle access for collection if required.
G15: Solid waste
In an (almost) welcome departure from the previous topic, G15 moves on to discuss garbage. The clause calls for sufficient size and space for disposal and capable sanitary solutions. Likewise, the purpose is also to uphold the safety of users. Facilities affected include garbage chutes, bins, and trash compactors.
H: Energy efficiency
In a welcome departure from the lengthy G-section, H delivers but a single clause, discussing energy efficiency, performance, and conservation.
H1: Energy efficiency
The building code delivers a remarkably brief objective for this section: to facilitate the efficient use of energy. In a bid to curb our growing energy usage, promoting efficiency is the clear way forward. The functional demands of this clause call for buildings to be constructed to achieve an adequate degree of energy efficiency in the case of HVAC, hot water, and artificial lighting. H1 extends past the interiors, however, with performance clauses that call for the building practitioners to take into account conditions such as the thermal mass of building elements, as well as the building’s orientation and shape. Insulation is highly important in this clause as it helps limit heat loss. Affected elements include the majority of building envelope components, heating systems, lights, hot water systems, and more.
While reading the building code may seem monolithic, it is always helpful to understand the reasoning behind their choices. While the stringent demands are oftentimes confusing and sometimes even contradictory, it can never hurt to learn more. If you would like more technical details, then perusing through New Zealand official building website can prove useful, which offers an accessible, colour-coded guide to the building code components, as well as direct links to the code itself.
Disclaimer: This article is for general educational purposes only. It is not a comprehensive manual of the New Zealand Building Code and has not been prepared by a trained or experienced building professional. The information provided is intended to give homeowners a broad, easy-to-understand overview of the NZ Building Code. It should not be relied upon as a substitute for professional advice or used as a reference for legal or compliance purposes. For accurate, detailed, and up-to-date requirements, please consult the official New Zealand Building Code and seek guidance from qualified building professionals.
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