If you're looking at a brick home in New Zealand, you might assume all brick walls are built the same way — but there are actually two quite different construction methods: brick veneer and solid brick (sometimes called double brick or solid masonry). Understanding which type your home has matters a great deal when it comes to maintenance, repairs, insulation, and compliance with the NZ Building Code.
What Is Solid Brick Construction?
Solid brick (or double brick) walls are built from two or more layers of brick that together form the structural wall of the building. The bricks themselves carry the load of the roof and floors — there is no separate timber or steel frame doing that job. Solid brick construction was common in New Zealand commercial buildings and some older homes, particularly those built before the mid-20th century.
Key characteristics of solid brick:
- Walls are typically 230 mm or more thick
- The bricks are the structural element — they hold the building up
- Very heavy and thermally massive (slow to heat up, slow to cool down)
- Common in pre-1950s NZ buildings and heritage structures
- Repairs and alterations can affect structural integrity
What Is Brick Veneer Construction?
Brick veneer is by far the most common form of brick construction in modern New Zealand homes. Despite looking identical from the outside, brick veneer is fundamentally different: a single layer of bricks is attached to the outside of a timber (or steel) framed wall, acting purely as a cladding — not as a structural element. The timber frame carries all the loads.
Key characteristics of brick veneer:
- Walls have a single skin of brick (typically 110 mm thick) tied to a timber frame with wall ties
- A cavity (usually around 25–50 mm) sits between the brick and the frame, allowing drainage and ventilation
- The timber frame is the structural element; the brick is the weatherproof cladding
- Lighter overall than solid brick
- The vast majority of NZ brick homes built from the 1960s onwards are brick veneer
- Governed by NZS 3604 (Timber-framed buildings) and the NZ Building Code
How to Tell Which Type You Have
The easiest way to identify your wall type is to check the wall thickness and look for weep holes.
| Feature | Solid Brick | Brick Veneer |
|---|---|---|
| Wall thickness | 230 mm+ | ~110 mm brick + frame (270–300 mm total) |
| Weep holes at base | No | Yes (every few bricks) |
| Internal wall finish | Brick or plaster on brick | Plasterboard on timber frame |
| Structural role of brick | Yes — load-bearing | No — cladding only |
| Common NZ era | Pre-1960s | 1960s to present |
| Cavity between brick & frame | No | Yes |
Weep holes — small gaps left in the mortar joints at the base of the brick course — are a tell-tale sign of brick veneer. They allow any moisture that enters the cavity to drain out. If you see a row of small open vertical joints near the bottom of the exterior brickwork, you almost certainly have brick veneer.
You can also check inside: if your interior walls are lined with GIB plasterboard on a timber frame, it's brick veneer. Solid brick homes typically have plaster applied directly to the masonry, or exposed brick internally.
Insulation and Energy Efficiency
This is where the two systems differ significantly. Brick veneer homes have a timber-framed cavity wall, which means insulation batts can be installed in the wall framing — a real advantage for meeting the Energywise recommendations and the NZ Building Code's energy efficiency requirements (Clause H1).
Solid brick walls have very limited options for retrofitting insulation without significant work. Their thermal mass can help moderate temperatures, but in NZ's often cool and damp climate, uninsulated solid brick walls can contribute to cold, damp interiors — a concern under the Healthy Homes Standards for rental properties.
Maintenance and Common Issues
Brick Veneer Maintenance
- Wall ties can corrode over time, particularly in older homes. Corroded ties can cause the brick skin to bow or crack — a job for a qualified bricklayer to assess.
- Weep holes must be kept clear to allow drainage from the cavity. Blocked weep holes can lead to moisture build-up and timber frame damage.
- Mortar repointing is routine maintenance. Cracked or eroded mortar lets water in and should be addressed promptly.
- Flashing around windows, doors, and the base of the wall is critical — refer to BRANZ guidance for best practice details.
Solid Brick Maintenance
- Cracked or spalling bricks and failed mortar joints are more serious, as the wall is structural.
- Any significant cracking should be assessed by a structural engineer or experienced bricklayer before repair work begins.
- Repointing is still the most common maintenance task, but matching heritage mortar mixes is important — using modern high-strength mortar on old soft bricks can cause damage.
When to Call a Professional
While minor repointing of small areas is something a confident DIYer can tackle, most brickwork repairs are best left to a qualified bricklayer — especially if you have:
- Cracking or bowing in the brick skin (could indicate wall tie failure or structural movement)
- Solid brick walls with significant damage (structural implications)
- Flashing or damp-proof course issues (involves weathertightness compliance)
- Any work that may affect the NZ Building Code compliance of your home
For solid brick buildings, structural alterations — such as cutting openings for new windows or doors — will likely require a building consent from your local council and may need input from a structural engineer. Check the requirements at MBIE Building Performance.
You can find qualified, experienced local bricklayers on tradedirectory.co.nz to assess and carry out any work safely and to code.