Replacing a damaged lintel above an internal doorway is technically possible as a DIY project in some situations, but it carries real structural risk and may require a building consent depending on the scope of work. Before you pick up a hammer, it's worth understanding exactly what a lintel does, what the rules are in New Zealand, and whether this is a job best left to a professional.
What Does a Lintel Actually Do?
A lintel is a horizontal structural member that spans the top of a door or window opening. Its job is to transfer the load from the wall and roof structure above the opening down to the surrounding framing on either side. If a lintel is undersized, rotted, cracked, or missing, the wall above can sag, doors can jam, and in serious cases the structure can be compromised. This is why lintel replacement is not a purely cosmetic job — it's structural work.
Is a Building Consent Required?
This is the critical question. Under the New Zealand Building Code and the Building Act 2004, any work that affects the structure of a building generally requires a building consent. However, Schedule 1 of the Building Act lists certain exemptions for minor work.
Replacing a like-for-like lintel in a non-loadbearing internal wall may fall under a Schedule 1 exemption (specifically, repair and maintenance using the same or similar materials). However, if the wall is loadbearing, or if you are changing the size of the opening, a building consent is almost certainly required.
How do you know if your wall is loadbearing? This isn't always obvious. Walls that run perpendicular to floor joists, sit above foundation piles, or support roof structure above are often loadbearing. If you're unsure — and many homeowners are — you should consult a Licensed Building Practitioner (LBP) or a structural engineer before doing anything.
Always confirm consent requirements with your local council before starting work. You can find general guidance at MBIE Building Performance.
NZ Framing Standards: What Size Lintel Do You Need?
Lintel sizing in New Zealand is governed by NZS 3604:2011 (Timber-framed buildings), which specifies minimum lintel sizes based on the load they carry, the span of the opening, and the roof and floor loads above. Getting this wrong can have serious consequences.
For example, a lintel in a non-loadbearing wall carries very little load and may only need to be a single 90×45 mm timber. A lintel in a loadbearing wall over a wider opening may need to be a doubled or tripled member, or even an LVL (laminated veneer lumber) beam. BRANZ publishes useful guidance on timber framing that can help you understand the principles involved.
What the DIY Process Involves
If you've confirmed the wall is non-loadbearing, the opening size isn't changing, and your council agrees no consent is needed, here's a general overview of what lintel replacement involves:
- Temporary support: Before removing the damaged lintel, you must install temporary props or acrow props to support the wall framing and any load above. This step is non-negotiable — skipping it risks wall collapse.
- Remove lining: Internal wall linings (typically GIB plasterboard) on both sides of the wall need to be carefully cut back to expose the framing.
- Remove and replace the lintel: The damaged timber is removed and a correctly sized replacement is fitted, nailed or bolted as required by NZS 3604.
- Reinstate framing: Any damaged noggings, jack studs, or trimmer studs are repaired or replaced.
- Reinstate linings: GIB is patched or replaced, stopped, and painted to match.
This is a multi-trade job — it touches carpentry, plastering, and painting. Materials like replacement timber, GIB, stopping compounds, and paint are available from Bunnings, Mitre 10, or PlaceMakers.
Safety Considerations
Temporary propping is the most critical safety step. A wall that is inadequately supported during lintel removal can shift or collapse, causing serious injury. If you are not confident in setting up temporary propping correctly, stop and call a professional. WorkSafe NZ has guidance on working safely around structural elements.
Also be aware that older homes (pre-1980s) may have asbestos in wall linings, textured coatings, or insulation. If your home was built before 1990, have the materials tested before cutting into walls.
When to Call a Professional
You should engage a Licensed Building Practitioner (LBP) or a qualified builder in these situations:
- The wall is or may be loadbearing
- You are enlarging the opening or changing the door size
- A building consent is required
- You are unsure about temporary propping or lintel sizing
- The damage is extensive or the cause is unknown (e.g. subsidence, moisture damage)
- Your home is older and may contain asbestos
Restricted building work — which includes structural work on loadbearing elements — must be carried out or supervised by an LBP under the Building Act. You can verify a tradesperson's licence at Licensed Building Practitioners. Find a qualified local builder on tradedirectory.co.nz.
As a rough guide, hiring a builder for a straightforward internal lintel replacement (non-loadbearing, no consent required) might cost anywhere from $500 to $1,500+ depending on the extent of damage and reinstatement required — but get quotes from local tradespeople for an accurate figure.
Sources & Further Reading
- MBIE Building Performance – Building consents and exemptions
- Licensed Building Practitioners – Find or verify an LBP
- BRANZ – Building research and technical guidance
- GIB – Plasterboard products and installation guides
- WorkSafe NZ – Health and safety guidance
- Standards NZ – NZS 3604 Timber-framed buildings
Registered Master Builder
Licensed Building Practitioner (LBP)
