How to Build a Garden Wall
Build a solid, attractive garden wall that lasts decades - from foundation to coping.
Difficulty
Hard
Time
2-3 days
Cost
£200 - £800
Before You Start
Check for underground services (gas, electric, water, drainage) before digging foundations. You can request plans from your utility companies or hire a cable avoidance tool (CAT scanner). Walls over 1 metre high may need Building Regulations approval. Walls over 2 metres need planning permission. Wear steel-toe boots, gloves and safety goggles when cutting bricks.
Building a garden wall is one of the most rewarding DIY projects you can tackle. A well-built brick wall adds genuine value to your property and lasts for generations. The key to a good wall is the foundation - skimp on this and the wall will crack and lean within a few years. Allow a full day just for the foundation and let it cure before you start laying bricks. If you have never laid bricks before, practice on a small section first.
What You Will Need
Tools
- - Bricklaying trowel
- - Spirit level (1 metre)
- - Builder's line and pins
- - Spade and wheelbarrow
- - Brick bolster and club hammer
- - Pointing trowel
- - Tape measure
- - Mixing board or cement mixer
Materials
- - Bricks (calculate: 60 per square metre for single skin)
- - Cement, sharp sand, soft sand
- - Concrete for foundations (1:3:6 mix)
- - Mortar (1:5 cement to soft sand, or use mortar mix)
- - Coping stones or brick-on-edge for top
- - DPC (damp proof course) strip
- - Plasticiser (makes mortar workable)
Step-by-Step Instructions
Plan and Mark Out
Decide on the wall position, height and length. Use string lines and pegs to mark the line of the wall. Check you are not building on top of any services. For walls over 1 metre, consider getting a structural engineer to specify the foundation.
Dig the Foundation Trench
Dig a trench at least 300mm deep and three times the width of the wall. The bottom must be firm, undisturbed ground. In clay soil, go deeper (450mm). Level the bottom of the trench.
Pour the Concrete Foundation
Mix concrete at a ratio of 1 part cement, 3 parts sharp sand, 6 parts aggregate (or use ready-mixed). Pour into the trench to a depth of at least 150mm. Level the top with a screed board. Leave to cure for at least 24 hours, ideally 3 days.
Dry-Lay the First Course
Lay bricks along the foundation without mortar to check the spacing. Aim for a 10mm gap between each brick. Adjust the spacing so you minimise the number of cut bricks. Mark the brick positions on the concrete.
Lay the First Course
Spread a bed of mortar 10mm thick along the foundation. Press the first brick into it and check it is level. Butter the end of the next brick with mortar and press it against the first, leaving a 10mm joint. Continue along the line, checking level every 3-4 bricks with a spirit level.
Build the Ends (Corners) Up First
Build each end of the wall up by 4-5 courses, stepping back each course by half a brick (like a staircase). Check each course is level and plumb (vertically straight). Stretch a builder's line between the raised ends and use it as a guide to fill in the middle courses.
Lay Subsequent Courses
Apply mortar to the top of the previous course and lay bricks in a stretcher bond pattern (each brick overlaps the one below by half). This is the standard pattern for a single-skin wall. Check level and plumb constantly. Keep mortar joints consistent at 10mm.
Point the Joints
Once the mortar is firm but not fully hard (thumb-print firm), use a pointing trowel or jointing tool to finish the joints. A bucket-handle or weatherstruck profile sheds water best. Brush off excess mortar crumbs.
Fit the Coping
Cap the wall with coping stones, brick-on-edge, or a concrete coping. This protects the wall from rain penetration. Bed the coping in mortar and ensure it overhangs the wall by at least 15mm on each side to throw water clear.
Cure and Protect
Keep the wall damp for 3 days by covering with polythene or spraying with water in hot weather. This allows the mortar to cure properly. Do not lean anything against it or apply loads for at least 7 days.
Pro Tip: Consistent Mortar
Mix small batches and keep the consistency the same throughout. Mortar should hold its shape on the trowel without slumping. Too wet and it squeezes out; too dry and the bricks will not bond.
Pro Tip: Butter Generously
Apply a generous amount of mortar to each brick end. When you press the brick into place, the excess squeezes out and you scrape it off. Thin mortar joints are weaker and more likely to crack.
Common Mistakes to Avoid
- - Skimping on foundation depth - the wall cracks and leans within a few years
- - Not checking level on every course - errors compound and the wall visibly leans
- - Mortar too wet - it squeezes out, stains the bricks and creates weak joints
- - Not wetting bricks in hot weather - dry bricks suck moisture from the mortar before it sets
- - Forgetting DPC between the wall and any adjacent structure - moisture travels through and causes damp
- - Trying to build too high in one day - mortar needs time to set or lower courses compress under the weight
When to Call a Professional
For retaining walls (holding back earth), walls over 1.2 metres high, or walls that adjoin your house, consult a structural engineer and use a professional bricklayer. Load-bearing walls and walls near boundaries are subject to the Party Wall Act. If in doubt, check with your local Building Control office.