Installing a pet door through a brick veneer wall is technically possible as a DIY project, but it's significantly more involved than cutting through a timber-framed wall with weatherboard cladding. Brick veneer walls have multiple layers, a critical cavity, and weathertightness requirements under the NZ Building Code that must be maintained. Before you pick up an angle grinder, it pays to understand exactly what you're dealing with.
What Is a Brick Veneer Wall?
A brick veneer wall is not a solid brick wall. It consists of:
- An inner timber-framed wall (typically 90 mm studs)
- A cavity (usually 40–50 mm) that allows moisture to drain and air to circulate
- A single skin of brick (approximately 110 mm thick) on the outside
- A cavity closer or flashing at openings to prevent moisture ingress
This cavity is critical. It's part of how your home manages moisture under NZ Building Code Clause E2 (External Moisture), and any penetration through the wall must be detailed correctly to keep water out.
Do You Need a Building Consent?
This is the first question to answer. Under the Building Act 2004, some minor work is exempt from building consent under Schedule 1, but the exemptions have conditions. A small pet door opening may qualify as exempt work if it doesn't affect the structural integrity of the wall and is properly weatherproofed — but this is not guaranteed.
Brick veneer walls can have brick ties and lintels that are structural elements. Cutting through without understanding the wall's construction could compromise these. Always check with your local council before starting, as consent requirements vary and the consequences of unlicensed structural work can be significant. You can find general guidance at MBIE Building Performance.
What's Actually Involved in the Job?
Here's a realistic overview of the steps:
1. Locate the Right Spot
- Avoid brick ties (metal wall ties connecting the brick to the frame — spacing varies; check with your builder or refer to NZ Standards guidance)
- Avoid studs in the inner frame if possible, or plan to trim and re-support around them
- Check for electrical cables or plumbing inside the wall before cutting (use a stud finder and cable detector)
2. Cut Through the Inner Lining and Frame
- Remove internal lining (typically GIB plasterboard — see GIB for repair guidance)
- Cut and frame the opening with a trimmer stud and nogging to maintain wall integrity
3. Cut Through the Brick
- Use an angle grinder with a diamond blade or a core drill for cleaner cuts
- Cut carefully to avoid cracking surrounding bricks
- This is dusty, noisy, and physically demanding work — wear appropriate PPE including a P2 respirator, eye protection, and hearing protection as required by WorkSafe NZ
4. Install Cavity Flashings and a Lintel
- A lintel (steel or concrete) must support the brickwork above the opening — even for a small pet door, the bricks above need support
- Cavity flashings must be installed to direct any moisture that enters the cavity out and away from the opening
- This is the most technically critical step and where most DIY attempts fall short
5. Install the Pet Door and Seal
- The pet door frame must be correctly flashed and sealed to both the brick and the inner frame
- Use a flexible, paintable sealant compatible with masonry (products from Sika are commonly used for this)
- Make good the internal plasterboard and repaint
Tools You'll Need
| Tool | Purpose |
|---|---|
| Angle grinder + diamond blade | Cutting through brick |
| Oscillating multi-tool | Cutting internal lining |
| Stud finder / cable detector | Locating hidden services |
| Masonry drill | Pilot holes |
| Spirit level | Keeping the opening square |
| Trowel and mortar | Repointing cut edges |
Is This a DIY Job?
For a confident, experienced DIYer with masonry experience, a small pet door installation may be achievable — but it is not a beginner project. The risks include:
- Structural damage if a lintel is omitted or incorrectly sized
- Moisture ingress if cavity flashings are incorrect, leading to costly damage over time
- Cracked or spalled brickwork from poor cutting technique
- Consent issues if the work is later found to be non-compliant
For most homeowners, this is a job best left to — or at least started with advice from — a Licensed Building Practitioner (LBP). You can verify a builder's licence at Licensed Building Practitioners.
When to Call a Professional
Call a qualified builder if:
- You're unsure whether consent is required
- You can't confidently identify brick ties, lintels, or hidden services
- The opening is near a corner, window, or door (more complex structurally)
- Your home is older and the wall construction is unknown
- You want the work to be covered by a building consent and code compliance certificate for future sale or insurance purposes
A good local builder can often complete this job in a day and ensure the weathertightness and structural details are done correctly. Find qualified builders in your area on tradedirectory.co.nz.
Note on electrical work: If you discover electrical cables inside the wall during this project, do not attempt to move or work around them yourself. Any alteration to wiring is restricted electrical work and must be carried out by a registered electrician — see EWRB for more information.
Registered Master Builder
Licensed Building Practitioner (LBP)
