What is Restricted Building Work (RBW) in NZ?
Short answer
Restricted Building Work (RBW) is design or construction work on the primary structure, the primary weathertightness envelope, or the fire safety system of a residential house. By law, RBW must be carried out or supervised by a Licensed Building Practitioner. The list is in the Building (Definition of Restricted Building Work) Order 2011 — and it's broader than most homeowners realise.
Source: Building (Definition of Restricted Building Work) Order 2011. Updated May 2026.
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- Defined in the Building (Definition of Restricted Building Work) Order 2011
- Covers primary structure, weathertight envelope, fire safety
- Includes most residential work touching framing, cladding, roofing, windows
- Must be done OR supervised by an LBP
- DIY exemption (Section 90B) lets owners do RBW on their own home but only with sign-off
What counts as RBW
Primary structure: foundations, framing, roof structure, load-bearing walls. Weathertight envelope: roofing, exterior cladding, exterior windows and doors. Fire safety: passive fire separation in multi-dwelling settings.
What doesn't: cabinetry, painting, flooring, internal joinery, tiling, basic plumbing fittings, internal trim, fences under 2.5m, decks under 1.5m.
DIY exemption (Section 90B)
An owner can do RBW on their own home if they apply for and receive a DIY exemption from the council. The owner must demonstrate skills or get an LBP to supervise. The exemption applies to one dwelling only — you can't use it on rentals or your spec build.
Practical advice: most homeowners find it easier to engage an LBP than apply for the exemption. The fee saved rarely covers the time and risk.
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Related questions
Sources: Building (Definition of Restricted Building Work) Order 2011; Building Act 2004 sections 84B-D and 90B. General information for NZ homeowners, not legal advice. Building rules change and vary by council, so confirm critical details on the official source before acting. Last updated 2026-05.