How to plan a brick garden wall
A garden wall is only as good as its footing. Plan the work from the ground up and save each step to one job, so the cement for the footing and the mortar ends up on one line of your shopping list.
- Set out and dig. Mark the wall line with string and pegs, then dig the trench down to firm, undisturbed ground.
- Pour the footing. Level the concrete and leave it at least a couple of days to harden before building on it.
- Build below ground. The first courses below ground level are part of the wall: our garden wall guide counts them for you.
- Build up and finish. Lay to a line, check level and plumb every few courses, and finish with a coping or a brick-on-edge course to keep rain out.
For footing sizes, mortar mixes and the full build, read the complete garden wall guide, which also has a wall planner priced at UK merchants.
What a 6m wall, 1m high, needs
A trench 450mm wide and 600mm deep along 6m is about 1.6m³ of soil, over 2m³ once it's dug and around 3 tonnes of clay, so book a small skip that takes heavy waste. In step 3, choose the Garden wall preset and set the width to match your trench. The wall itself needs about 400 bricks in single skin, or about 800 in double skin, plus a few more for the courses below ground. The mortar for 400 bricks is roughly 3–4 bags of cement and a third of a tonne of building sand.
Single skin with piers, or double skin?
A 1m single-skin wall needs piers, thicker brick columns about every 2–3m, to resist wind and knocks. A double-skin wall needs no piers, looks finished from both sides, and suits most free-standing walls at this height. It uses twice the bricks but less cutting round piers. For anything holding back soil, use the retaining wall calculator instead. That's a different, stronger build.
Timing and weather
Allow a day to dig and pour the footing, then leave it to harden for a couple of days. Build up to about 1–1.2m in a day or two, checking level and plumb every few courses. Don't lay bricks when frost is forecast, cover new work overnight, and avoid heavy rain, which washes mortar out of fresh joints and stains the face.
Common mistakes
- A footing that's too small or too shallow. This is the main cause of cracked, leaning garden walls.
- No coping. Water soaking into the top of the wall freezes and breaks the bricks and joints.
- Bricks not rated for exposure. Use frost-resistant bricks, as a garden wall gets wet on both sides.
For mortar quantities on their own, use the mortar calculator.