How to Build a Brick Garden Wall

A brick garden wall is one of the most satisfying DIY building jobs: it lasts a lifetime and adds real value to a garden. It's also a job where small shortcuts, like a thin footing, the wrong thickness or laying in a frost, show up a year later as cracks and leaning. This guide walks you through every decision in order, and the wall planner below costs your whole wall (footing, below-ground brickwork and coping included) with today's UK merchant prices.

Planning the whole job? Our Brick garden wall planner takes your measurements once and builds a single shopping list across every calculator you need.

1. Check the rules before you buy a brick

• Height and planning. In England, walls, fences and gates are permitted development up to 1m high next to a road used by vehicles (or the footpath beside it) and 2m high elsewhere. Taller than that needs planning permission. If your home is listed, in a conservation area, or has had its permitted development rights removed, ask your council first. Wales has similar rules; Scotland and Northern Ireland have their own.
• On the boundary? If the wall will sit on or astride the boundary line with a neighbour, the Party Wall etc. Act 1996 applies in England and Wales: you need to give your neighbour written notice before you start. Building wholly on your own side avoids this, but talk to them anyway. A wall going up next door is a classic source of disputes.
• Is it holding back soil? This guide is for freestanding walls. A wall that retains a bank of earth carries far bigger loads and needs a different design; see the retaining wall calculator and get advice for anything over about 1m of retained soil.
• Look before you dig. Check for drains, water pipes and cables along the line of the trench, and keep clear of big tree roots, which can lift or crack a wall as they grow.

2. Single or double skin?

This is the biggest decision, because it fixes how tall the wall can safely be, what it looks like and how many bricks you need.

Piers are short thickened sections, usually one brick square (215 × 215mm) or more, built into the wall at the ends and every 2–3m along it. They stiffen a single-skin wall the way the corners of a box stiffen its sides. If you want a wall much over a metre and don't want piers, build double skin.

Coping is the top course. Its job is to stop rain soaking down into the wall, which is what causes frost damage and white salt staining. A brick-on-edge course (bricks stood on their side across the top) is traditional on a double-skin wall; coping stones with an overhang and a drip groove shed water best.

3. Plan and cost your wall

Enter your wall and the planner works out everything it needs: the bricks for the wall above ground, the brickwork below ground down to the footing and the coping course, the mortar, and the concrete for the footing. Then it prices the lot at the cheapest UK merchant we've found. Most brick calculators only count the bit you can see.

Assumes standard 215 × 102.5 × 65mm bricks with 10mm joints, 10% extra for cuts and breakages, 4:1 mortar (about 720kg of building sand and 7.5 bags of cement per 1,000 bricks), and a 225mm-thick footing 300mm longer than the wall in a 1:5 cement and all-in ballast mix. Not included: coping stones for a single-skin wall, plasticiser, and tool or mixer hire.

4. What goes under the ground

The footing is the part nobody sees and the part that decides whether the wall is still straight in 30 years. It spreads the weight of the wall over a wider strip of firm soil, so it can't sink unevenly or tip.

• Width: about 450mm for a single-skin wall and 600mm for a double-skin wall, centred under the wall.
• Thickness: 150–225mm of concrete. Go for the thicker end on clay, made-up ground or for taller walls.
• Depth: dig through all the topsoil onto firm, undisturbed ground. On most garden soils that puts the bottom of the trench around 450–600mm down; on shrinkable clay or near trees, dig deeper. For walls over about 1.8m, or anything unusual, get a builder or engineer to size the footing.
• Concrete: for a short wall, mix 1 part cement to 5 parts all-in ballast. Every 1m³ takes about 14 bags (25kg) of cement and 1.7 tonnes of ballast. For more than about 1m³, ready-mix delivered to the drive is usually less work and not much dearer. The concrete calculator and the foundation calculator do the sums.
• Level: drive timber pegs into the trench with their tops at the finished concrete level, checked with a level, then fill to the tops of the pegs. A level footing makes every course above it easier.
• Let it harden: give the concrete at least a couple of days before you start bricklaying on it, and keep it covered so it doesn't dry out too fast in sun or wind.

5. Building the wall, step by step

1. Set out. Mark the line of the wall with pegs and string. For a corner, check it's square with the 3-4-5 rule: 3m along one side, 4m along the other, and the diagonal should be exactly 5m.
2. Make a gauge rod. Mark a straight timber batten every 75mm (one brick plus one 10mm joint). Holding it against the ends of the wall keeps every course the same height, so the joints line up all the way along.
3. Dry-lay the first course. Lay the bottom course on the footing without mortar, with 10mm gaps, to see where cut bricks will fall. Adjust so cuts land somewhere unobtrusive, not at a visible end.
4. Mix the mortar. Use a 3:1 building sand to cement mix for the courses below ground and 4:1 for the wall above, with plasticiser rather than washing-up liquid. It should be soft and buttery and hold its shape on the trowel. Mix small batches: only what you'll use within about two hours.
5. Build the ends first. Build each end (or pier) up 4–6 courses as a stepped "lead", checking it's level, plumb and to the gauge rod on every course. These are your guides for everything in between.
6. Run the line and fill in. Stretch a brick line between the ends at the top of the next course, and lay the bricks in between to the line. Keep the face clean and the joints full. Hollow joints let water in.
7. Finish the joints. When the mortar is thumb-print hard, run a jointing tool along the joints for a curved "bucket handle" finish, then brush off the crumbs. It looks neat and sheds rain.
8. Lay the coping. Bed the coping in 3:1 mortar, with full joints and no gaps, so water can't get in at the top.
9. Protect it. Cover the top of new brickwork overnight and in rain, and don't let it dry out in hot wind. Fresh mortar must not freeze.

6. Weather and timing

• Cold: don't lay bricks when it's 3°C and falling, or if frost is forecast before the mortar has had a day or two to set. Frozen mortar crumbles and has to be raked out.
• Rain: wet bricks slide and smear, and rain washes cement out of fresh joints and stains the face. Keep the bricks covered and stop when it's heavy.
• Heat: on hot, windy days mortar stiffens quickly. Mix smaller batches and lightly damp very dry, thirsty bricks.
• Pace yourself: experienced bricklayers lay several hundred bricks a day; a first-timer laying neatly will manage far fewer. A wall built slowly and accurately looks better than one rushed, and it's normal to build a long wall over a few weekends.

7. Ten mistakes that ruin garden walls

1. No footing, or a thin one. Bricks laid on a few slabs or straight onto soil will crack and lean.
2. Too tall for the thickness. A single-skin wall over about 1m without piers can be pushed over by wind or a leaning person.
3. Ordinary bricks below ground. Use frost-resistant (F2 rated) facing bricks, or engineering bricks, for the courses in contact with the soil.
4. No coping, or a leaky one. Water soaking down from the top is the main cause of frost damage and white salt staining (efflorescence).
5. Weak or old mortar. Mortar that's been sitting for hours, or has been re-wetted, never reaches full strength.
6. Hollow joints. Gaps in the joints let water in and look scruffy. Fill every joint fully.
7. Not keeping to gauge. Without a gauge rod, courses creep up or down, and the ends no longer line up.
8. Laying in frost. The joints will fail. Wait for the weather.
9. Mixing brick batches. Bricks vary in colour between batches. Order them all at once and mix bricks from several packs as you go, to avoid stripes and patches.
10. Using a plastic DPC in a freestanding wall. A garden wall isn't a house wall, and a plastic damp-proof course can act as a sliding joint that weakens it. If you want one, lay a couple of courses of engineering bricks instead.

8. Printable checklist

Print this page (the planner is left out of the printout) and tick these off as you go:

• Height checked against planning limits, and neighbour told (or Party Wall notice served)
• Drains, pipes and cables checked along the line
• Single or double skin decided, and piers planned if needed
• Bricks, cement, sand and ballast ordered in one go (frost-resistant bricks for below ground and coping)
• Line set out, square checked with 3-4-5
• Trench dug to firm ground, pegs set level
• Footing poured, levelled and left to harden for a couple of days
• Gauge rod marked at 75mm, first course dry-laid
• Ends or piers built up as leads, level and plumb
• Courses filled in to the line, joints finished when thumb-print hard
• Coping laid in 3:1 mortar
• New work covered against rain and frost

Ready to work out quantities for a different wall? Use the brick calculator for the brickwork, the mortar calculator for a different mix, or the concrete calculator for the footing.