Building Class
Overview
This article explains the building classifications under the National Construction Code (NCC) and when parts of a building require separate classification due to different uses.
Why This Is Important
- Ensures buildings are classified correctly for compliance with NCC regulations.
- Helps determine which code volume applies to the building design.
- Clarifies when mixed-use areas must be separately classified.
How to Understand Building Classifications
1. NCC Volumes and Classes
- Building classifications are labelled “Class 1” through “Class 10.”
- Some classes have sub-classifications indicated by a letter (e.g., Class 1a).
- Class 2 to 9 buildings are mainly covered by Volume One of the NCC.
- Class 1 and 10 buildings are mainly covered by Volume Two of the NCC.
2. Mixed-Use Buildings
- A building can have parts with different uses.
- In most cases, each part must be classified separately.
Example:
- A single-storey warehouse (Class 8) with an office (Class 5).
- If the office takes up 8% of the floor area, the whole building can be classified as Class 8.
- If the office takes up 12%, it must be classified separately (Class 8 and Class 5).
3. Ancillary Use Rule
- Where a part has a different purpose but is not more than 10% of the floor area, it may be considered ancillary to the major use.
- This simplifies classification when the secondary use is minor.
Tips, Best Practices & Troubleshooting
- Always confirm the floor area percentage of different use areas before classifying.
- Refer to the NCC Volumes to check specific requirements for each class.
- Document any decisions about ancillary use or mixed classifications.
Related Resources
Class 10 Buildings or Structures
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Review & Updates
Version History:
- v1.0 –10 March 2024
- v2.0 – 31 July 2025
Article Information
- Category: Site Specific Engineering
- Target Audience: Franchise Users, Estimators, Sales Coordinators
- Business Owner:
- Version: v2.0
- Last Reviewed: 31 July 2025