How do i lay a simple garden or retaining brick wall? (2026)
Quick Answer
To lay a simple garden brick wall, start with a firm, level base, then build slowly from the corners using a string line to keep each course straight and level. For a low decorative wall, careful setting out and consistent mortar joints matter most; for any wall that retains soil, drainage and a suitable foundation are critical, and larger or higher retaining walls often need professional design and construction.
Overview
A simple brick garden wall is a manageable DIY job if it is low, non-structural and built on a proper base. The two big reasons walls fail are poor foundations and poor water management. A decorative boundary or edging wall mainly needs a stable footing, accurate layout and consistent bricklaying. A retaining wall has a harder job because it must resist sideways pressure from wet soil, so it also needs drainage behind it and may need reinforcement or engineering depending on its height, location and local rules. The basic process is: plan the wall, check services and local requirements, prepare a straight and level footing, dry-lay to confirm the pattern, mix and apply mortar according to the manufacturer’s instructions, build the corners first, run a string line between them, and keep checking level, plumb and joint consistency. Work neatly and do not rush the first course, because any error there carries through the whole wall. If you want a low garden feature, use bricks suitable for outdoor exposure. If the wall will hold back soil, slopes or heavy loads, be much more cautious. Exact footing sizes, drainage details and whether consent is needed vary by site, wall height, soil type and local regulations, so check official local guidance before you start.
Who this is for
Homeowners wanting to build a low, simple garden brick wall or very small retaining feature, and who are comfortable with basic digging, measuring and careful hand work.
What you’ll need
- bricks rated for exterior use
- mortar suitable for bricklaying, mixed exactly to the bag or manufacturer instructions
- foundation or footing materials appropriate for the wall type
- spade and digging tools
- tape measure
- string line and line pins
- spirit level
- brick trowel
- club hammer and bolster or a suitable brick-cutting tool
- wheelbarrow or mixing tray
- bucket and clean water
- jointing tool
- drainage material for retaining walls
- personal protective equipment
Before you start
Check whether the wall is purely decorative or will retain soil, because that changes the risk and build method. Confirm the boundary line, look for underground services before digging, and check local council requirements for retaining walls, front boundary walls and any work near drains or neighbouring land. Choose bricks and mortar suitable for external conditions in your climate. Read the mortar and brick manufacturer guidance before mixing or laying.
Step-by-step
- 1
Plan the wall and mark it out
Mark the wall line with string and pegs. Decide where corners, ends and any steps in the wall will go. For a retaining wall, identify where water behind the wall will drain to before you dig anything.
Why: A straight layout avoids awkward cuts and helps you spot problems with levels, boundaries and drainage before materials are wasted.
- 2
Prepare the footing or base
Excavate and build the footing or base to suit the wall type, site conditions and local requirements. For a simple garden wall, the footing must be firm, level and continuous. For a retaining wall, use a foundation approach suitable for the load and soil conditions, and do not guess the required dimensions.
Why: The footing spreads the load and keeps the wall from settling unevenly, leaning or cracking.
- 3
Set up guides and dry-lay the first course
Once the base is ready, dry-lay some bricks along the line to check the bond pattern, joint spacing and where cuts will fall. Set up line blocks or pins and run a taut string line at the face of the wall.
Why: Dry-laying helps you avoid tiny sliver cuts and awkward spacing, while the line keeps the wall straight from the start.
- 4
Mix mortar correctly
Mix only as much mortar as you can use while it is still workable, following the product instructions exactly. Keep the mix consistent from batch to batch. Do not add random extra water later to revive mortar that has already started to go off unless the manufacturer specifically allows it.
Why: Consistent mortar gives predictable bond strength and cleaner joints. Over-wet or retempered mortar can weaken the wall.
- 5
Lay the first course carefully
Spread a bed of mortar, place the first bricks at the ends or corners, then lay the rest of the first course to the line. Tap each brick into place, checking level along the top and plumb on the face. Fill vertical joints fully as you go.
Why: The first course controls everything above it. If it is not level, plumb and aligned, the whole wall will show it.
- 6
Build up corners first, then infill between them
Raise the corners a few courses, checking level and plumb repeatedly, then run the string line between them and fill in the middle. Stagger the vertical joints in a proper bond pattern rather than stacking them directly above each other.
Why: Corners act as guides for the rest of the wall, and a staggered bond helps the wall act as one unit instead of a stack of separate columns.
- 7
Add drainage if the wall retains soil
As a retaining wall goes up, place suitable free-draining material behind it and provide drainage details appropriate to the design and local practice. Keep soil and fine material from blocking drainage paths.
Why: Water pressure behind a wall causes many failures. Good drainage reduces pressure and helps the wall last.
- 8
Finish the joints and protect the work
When the mortar has firmed up enough, tool the joints neatly, brush off loose mortar and protect the wall from heavy rain, frost, strong sun or accidental knocks while it cures. Follow the mortar manufacturer’s curing and protection guidance.
Why: Proper joint finishing improves weather resistance and appearance, and early protection helps the mortar develop strength properly.
Why this works
A brick wall stays sound when loads are transferred down through bonded bricks into a stable footing, and when water is kept from building pressure or washing support away. Level courses, full mortar joints and proper drainage are the basics that make the wall behave as one structure.
Common mistakes to avoid
- Building on soil that is soft, uneven or not properly prepared
- Rushing the first course instead of getting it perfectly straight and level
- Using indoor or unsuitable bricks outdoors
- Mixing mortar by guesswork rather than following the product instructions
- Leaving vertical joints partly empty
- Stacking vertical joints directly above each other instead of using a proper bond
- Ignoring drainage behind a retaining wall
- Trying to build a retaining wall that is too large for DIY without design advice
Troubleshooting
The wall starts to wander off line
Stop and reset the string line, then correct gradually over the next bricks if the deviation is small. If the first course is badly out, lift and relay before the mortar hardens.
Courses are becoming uneven
Check whether the error began in the first course or at the corners. Recheck level and plumb at every brick for the next few placements rather than trying to hide the problem with thicker mortar joints.
Mortar is too wet and bricks slide out of place
Discard or adjust only as allowed by the manufacturer instructions, then remix to the correct consistency. Use smaller batches so the mortar stays workable without becoming soupy.
White staining appears later on the bricks
Allow the wall to dry out fully and follow the brick manufacturer’s cleaning advice. Improving drainage and preventing repeated saturation helps stop it returning.
A retaining wall shows bulging, leaning or cracking
Treat this as a warning sign of structural failure. Stop work, keep people clear and get professional advice before adding more height or backfill.
Compare your options
Low decorative garden wall
Best for: Edging, planting areas and simple visual boundaries
Pros: More suitable for careful DIY, simpler drainage needs, easier to keep straight and level
Cons: Still needs a proper footing and weather-suitable materials; not designed to hold back significant soil
Small brick retaining wall
Best for: Very modest level changes where local rules allow and the site is simple
Pros: Can create useful flat planting space and a tidy edge
Cons: Higher risk if built badly, drainage is essential, footing and design are more critical, often unsuitable for inexperienced DIY
| Option | Best for | Pros | Cons |
|---|---|---|---|
| Low decorative garden wall | Edging, planting areas and simple visual boundaries | More suitable for careful DIY, simpler drainage needs, easier to keep straight and level | Still needs a proper footing and weather-suitable materials; not designed to hold back significant soil |
| Small brick retaining wall | Very modest level changes where local rules allow and the site is simple | Can create useful flat planting space and a tidy edge | Higher risk if built badly, drainage is essential, footing and design are more critical, often unsuitable for inexperienced DIY |
Alternatives
- Use concrete retaining wall blocks designed for dry-stacking or reinforced retaining systems if you need a small landscape retaining wall
- Use timber or masonry edging for a purely decorative low border
- Hire a bricklayer for the visible brickwork while you do site clearing and simple preparation
Pro tips
- Buy a few extra matching bricks so cuts, breakages and later repairs are easier to handle
- Keep the face of the bricks clean as you go; hardened smears are harder to remove later
- Check level, plumb and line constantly rather than hoping to fix errors higher up
- If you are new to bricklaying, practise laying a short test section first
- On a visible wall, keep joint thickness visually consistent even more carefully than speed
Safety notes
- Wear gloves, eye protection and suitable footwear when cutting bricks and mixing mortar
- Cement-based products can irritate or burn skin, so wash off splashes promptly and follow the product safety information
- Watch for underground services before digging
- Do not work below or beside an unstable bank or partially failed retaining wall
- Lift bricks and bags safely; they are heavier than they look when handled repeatedly
Legal & regulatory notes
Requirements vary by country, region and council. In New Zealand, retaining walls and boundary structures can trigger consent or other rules depending on factors such as height, surcharge, location near boundaries or buildings, and whether the wall supports land carrying extra load. Always check with your local council before starting, especially for retaining walls.
What this guide does not cover: This guide covers only a simple low garden wall and very small retaining situations in general terms. It does not provide engineered footing sizes, drainage design, structural reinforcement details, consent advice for your exact site, or product-specific mortar and brick specifications.
Cost considerations
The main cost drivers are the footing or base, drainage materials for retaining walls, brick type, access to the site and whether you need professional design or consent. A decorative low wall is usually much cheaper than a retaining wall because retaining work often needs more excavation, drainage and engineering input.
Prefer to hire a professional?
If this job is beyond a confident DIY — or the work needs to be done by a licensed professional — you can find a verified gardener or landscaper through these directories of real, verified trade businesses. Compare local tradespeople, read their details and request quotes before you commit.
Frequently asked questions
Can I build a brick wall straight onto soil?+
No. Even a low wall needs a stable, suitable base or footing. Building straight onto bare soil greatly increases the chance of movement, cracking and leaning.
Do I need special bricks for a garden wall?+
Use bricks suitable for external exposure in your climate. Product suitability varies, so check the manufacturer information rather than assuming any spare brick will do.
Is a retaining wall harder than a normal garden wall?+
Yes. A retaining wall must resist soil and water pressure, so drainage, foundation design and sometimes engineering are much more important.
How do I keep the wall straight?+
Set accurate corner points, use a taut string line for every course, and keep checking level and plumb. Do not rely on eye alone.
When should I stop and call a professional?+
If the wall is retaining soil, close to a boundary or structure, showing movement, or you are unsure about footing design, drainage or consent, get professional help before continuing.
Sources & references
Guidance on this page is traced to documented sources. Last checked 25 September 2026.
- New Zealand Building Performance · government
Supports checking New Zealand building requirements and guidance for building work, including when consent or further technical guidance may be needed.
- BRANZ · industry
Supports good practice for residential construction in New Zealand and the importance of durable materials, sound foundations and weather-resistant detailing.
- Austral Bricks · manufacturer
Supports manufacturer-led guidance on using bricks suitable for exterior conditions, cleaning and handling masonry, and following product-specific recommendations.
Basic bricklaying practice changes slowly, but local council rules, consent thresholds and manufacturer product guidance can change and should be checked before starting.