How many bricks do I need?
A standard UK metric brick is 215 × 102.5 × 65mm. With 10mm mortar joints, each brick takes up 225 × 75mm of wall face, which works out at 59.26 bricks per m², rounded to 60 in the trade. A double-skin wall uses twice as many.
Bricks and mortar per m²
| Wall type | Bricks / blocks per m² | Building sand per m² | Cement per m² (4:1) |
|---|---|---|---|
| Single skin (102.5mm) | 60 bricks | ~43 kg | ~11 kg |
| Double skin (215mm) | 120 bricks | ~86 kg | ~22 kg |
| Cavity (brick + block) | 60 bricks + 10 blocks | ~59 kg | ~15 kg |
Brickwork tips
- Order all bricks from the same batch and mix from several packs as you lay to avoid colour banding.
- Lay a DPC (damp-proof course) at least 150mm above ground level on house walls.
- Build up the corners (leads) first, then fill in between them using a string line.
- Never lay bricks in frost, and protect new work from rain and frost with hessian or sheeting.
- For a cavity wall, use wall ties at 900mm horizontal and 450mm vertical centres, about 2.5 per m².
Worked example: a 6m garden wall, 1.2m high
In single skin, the wall is 7.2m², so 7.2 × 60 = 432 bricks, plus 10% = 476 bricks. The mortar is about 430kg dry: in a 4:1 mix that's 4 bags of cement and roughly 340kg of building sand, or 14 small bags. At 1.2m, that's 16 courses. A single-skin wall this tall needs piers about every 2–3m to stand up to wind, and the calculator reminds you of this.
Built as a double-skin (one-brick) wall, the same wall needs about 951 bricks and twice the mortar, but it's far sturdier and looks the same from both sides. For a free-standing garden wall over about 1m, it's usually the better choice.
Choosing bricks
- Facing bricks have a finished face for walls you'll see. For garden walls, choose ones rated frost-resistant (F2), because a garden wall gets wet on both faces and the top.
- Engineering bricks are dense and water-resistant. Use them below ground, for the first few courses on wet sites, or as a damp-proof course in garden walls.
- Common bricks are cheaper and fine where they'll be rendered or hidden.
- Reclaimed bricks look great next to old houses, but are often softer. Pair them with a weaker or lime mortar, and allow more for breakages.
Bonds and piers
A single-skin wall is laid in stretcher bond, each brick lapping half over the two below. Double-skin walls are tied together through the thickness with headers, in English or Flemish bond, and the brick count stays about 120 per m² whichever bond you choose. Piers (thicker columns of brickwork) stiffen long or tall walls. Allow a few extra bricks for each. Long runs of brickwork also need movement joints at intervals so the wall can expand and contract without cracking.
Common mistakes
- No proper footing. A wall on a shallow or crumbly base cracks within a few winters. The foundation calculator sizes the strip footing.
- Bricks from one pack at a time. Colour varies between packs. Blend three or four packs as you go to avoid obvious bands.
- No coping. Rain soaking into the top of a garden wall is the main cause of frost damage. Finish it with a coping or brick-on-edge course.
Our step-by-step garden wall guide covers footings, piers and coping with a priced planner. The brick garden wall planner puts the dig, skip, footing and bricks in one list. For mortar alone, use the mortar calculator.