Working out how many bricks you need for a garden feature wall is straightforward once you know your wall dimensions and the brick size you're using. The basic process involves calculating the wall's surface area, dividing by the face area of one brick (including mortar joints), then adding a waste factor. Get this right upfront and you'll avoid costly shortfalls or excess material sitting in your driveway.
Step 1 – Measure Your Wall Area
Start by measuring the length and height of your proposed wall in metres. Multiply these together to get the total face area in square metres (m²).
For example:
- Wall length: 4.5 m
- Wall height: 0.9 m
- Face area = 4.5 × 0.9 = 4.05 m²
If your wall has openings (gates, gaps), measure those separately and subtract them from the total area.
Step 2 – Know Your Brick Size
In New Zealand, the most common standard brick is the standard modular brick, which measures approximately 230 mm long × 110 mm wide × 76 mm high. However, brick sizes do vary between manufacturers and product ranges, so always confirm the exact dimensions with your supplier before calculating.
For a garden feature wall, you'll typically be looking at the face dimensions — length and height — plus the mortar joint. A standard mortar joint is 10 mm.
So the face area of one brick including mortar joint is:
- (230 mm + 10 mm) × (76 mm + 10 mm)
- = 240 mm × 86 mm
- = 0.240 m × 0.086 m
- = 0.02064 m² per brick
This means there are roughly 48–50 bricks per m² for a single-skin (half-brick) wall laid in a standard stretcher bond.
Step 3 – Decide on Wall Thickness
A garden feature wall is commonly built as a single-skin wall (one brick wide, roughly 110 mm thick) or a double-skin wall (two bricks wide, roughly 230 mm thick). Double-skin walls are stronger and better suited to freestanding walls over about 600 mm high.
| Wall Type | Thickness | Bricks per m² (approx.) |
|---|---|---|
| Single skin (stretcher bond) | ~110 mm | 48–50 |
| Double skin | ~230 mm | 96–100 |
| Single skin (soldier course) | ~110 mm | Varies — seek advice |
For anything other than a simple stretcher bond, the brick count per m² will change, so it pays to sketch out your bond pattern or ask your brick supplier for guidance.
Step 4 – Calculate Your Base Quantity
Multiply your wall face area by the number of bricks per m²:
Example (single-skin wall):
- 4.05 m² × 48 bricks/m² = 194 bricks
If you're building a double-skin wall, multiply by approximately 96–100 bricks/m².
Step 5 – Add a Waste Allowance
Always order more bricks than your calculated quantity. Bricks get cut, chipped, or cracked during handling and laying. A standard waste allowance is:
- 5–10% for straightforward walls with few cuts
- 10–15% for walls with curves, angles, or decorative features
Example continued:
- 194 bricks × 1.10 (10% waste) = 214 bricks — round up to the nearest full pack or pallet quantity.
Also order a small extra quantity to keep aside for future repairs, as brick colours and textures can vary between batches.
Step 6 – Don't Forget Mortar and Footings
Bricks alone won't build your wall. You'll also need to estimate:
- Mortar — as a rough guide, a 20 kg bag of mortar mix covers approximately 25–30 standard bricks (this varies by product and joint thickness; check the manufacturer's data sheet).
- Concrete footings — a freestanding garden wall needs a solid concrete foundation. The depth and width will depend on your soil type, wall height, and local conditions. Check with your local council or a qualified tradesperson for footing requirements in your area.
For mortar and adhesive products suited to brickwork, suppliers like Sika and Ardex offer a range of products with technical data sheets to help you estimate quantities accurately.
Building Consent and NZ Regulations
In New Zealand, many garden feature walls can be built without a building consent under Schedule 1 of the Building Act, but this depends on the wall's height, location, and proximity to boundaries or structures. As a general guide, low freestanding walls may be exempt depending on specific conditions — but always confirm with your local council before starting work, as exemptions have specific conditions. You can find general guidance at MBIE Building Performance.
For walls near boundaries, retaining walls, or anything structural, consent is more likely to be required.
When to Call a Professional
While calculating brick quantities is a DIY-friendly task, the actual construction of a freestanding masonry wall — especially one over 600 mm high — involves structural considerations that benefit from professional input. A Licensed Building Practitioner (LBP) or experienced bricklayer can advise on footing design, wall ties, drainage, and bond patterns to ensure your wall is safe and durable. You can find qualified local tradespeople on tradedirectory.co.nz.
A Quantity Surveyor (QS) can also help you prepare a full materials schedule and cost estimate if your project is more complex, helping you avoid over-ordering or budget blowouts.
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