127: The New Zealand Building Code: Clause B1 structure

The backbone of structural integrity in the New Zealand Building Code

For Licensed Building Practitioners (LBPs), Clause B1 is central to their responsibilities when designing, supervising, or carrying out Restricted Building Work (RBW).

What Clause B1 requires

Clause B1, titled Structure, requires that buildings, building elements, and sitework must withstand likely loads including wind, earthquake, live and dead loads, and other environmental actions. These requirements apply during construction, alteration, and throughout the life of the building. 

The clause includes mandatory objectives, functional requirements, and performance criteria. It makes allowances for the intended use of the building and the consequences of failure. Compliance can be demonstrated through Acceptable Solutions (for example, B1/AS1) and Verification Methods (for example, B1/VM1 and B1/VM2), which are published by the Ministry of Business Innovation & Employment (MBIE) and provide pathways for meeting the Code. 

What Is Restricted Building Work?

Restricted Building Work (RBW) is residential design and construction work that is critical to the structural integrity and weathertightness of homes and small-to-medium sized apartments. It includes work that:

• requires a building consent, and
• involves or affects a building’s primary structure, external moisture-management systems, or certain fire safety systems.

Examples of RBW related to Clause B1 include:

• foundations and subfloor framing
• load-bearing walls
• roof framing
• columns and beams
• bracing systems.

Because these elements directly relate to the structural stability of a building, they fall under the scope of Clause B1. Therefore, any RBW involving these components must comply with Clause B1’s performance requirements.

The role of Licensed Building Practitioners

Only Licensed Building Practitioners (LBPs) can carry out or supervise RBW. 

LBPs are legally required to document their involvement in RBW. Designers must provide a Certificate of Design Work, and builders must submit a Record of Building Work. These documents form part of the building consent process and help councils verify compliance with the Building Code. 

Accountability and ethics

LBPs are held to high professional standards, including a Code of Ethics, which sets principles such as working safely, acting within the law, taking responsibility, and behaving professionally.

Principle 2, You must act within the law, requires the LBP to ensure that the design or building work they carry out or supervise complies with, among other things, the Building Act and the building code.

This means LBPs are accountable for all building work they carry out, including the structural elements of the buildings they work on. 

Practical implications for LBPs

Clause B1 has direct implications for how LBPs plan, execute, and document their work. Key responsibilities include:

• ensuring that structural elements are designed and constructed to withstand expected loads
• using materials and methods that comply with Acceptable Solutions or Verification Methods
• supervising non-licensed workers and documenting that supervision in the Record or Certificate of Work
• staying up to date with changes to the Building Code and MBIE guidance.

Conclusion

Clause B1 is the structural foundation of the Building Code. It ensures that buildings are safe, stable, and durable. For LBPs, Clause B1 defines much of their professional responsibility, especially when undertaking Restricted Building Work.

By understanding and applying Clause B1 correctly, LBPs help protect the integrity of New Zealand’s homes and the safety of the people who live in them.

Quiz

1. What is the primary purpose of Clause BI of the NZ Building Code?
   

   1. To regulate plumbing and drainage systems

   2.  To ensure buildings are structurally sound and can withstand expected loads

   3.  To set out fire safety requirements for residential buildings

   4.  To provide guidance on energy efficiency in buildings

2. What are the two conditions that define Restricted Building Work (RBW)?
   

   1. Work that is carried out by apprentices and involves plumbing

   2.  Work that requires a building consent and affects primary structure, moisture management, or fire safety systems on a residential building

   3.  Work that is completed within 30 days and involves external cladding

   4.  Work that is supervised by a site manager and includes landscaping

3. According to MBIE’s Code of Ethics for LBPs, which of the following are core principles?
   

   1. Maximising profit

   2. Working safely and acting within the law

   3. Delegating all work to apprentices

   4. Avoiding documentation

4. What are two responsibilities of a Carpentry LBP under Clause B1?

1. 1. Designing the building’s fire escape routes

   2. Installing structural framing and bracing systems

   3. Approving building consents

   4. Supervising plumbing installations