A brick retaining wall stays put when it sits on a solid footing, uses consistent mortar joints, and has gravel and weep openings that let water drain out.
A brick retaining wall can tidy up a sloped yard fast. It holds soil in place, keeps mulch where it belongs, and gives planting beds a clean edge that won’t warp or rot. It’s also a small structure, not a stack of bricks. The base, bond pattern, and drainage all matter.
This build walks you through the choices that decide whether the wall stays straight: wall height, footing size, mortar selection, drainage, and the little habits that keep courses level.
Before You Break Ground
Confirm Height Rules And Set A Safe Target
Rules vary by place, yet retaining walls often trigger permits once they pass a certain retained height. One county guideline lists a permit trigger at over 36 inches retained height, plus other conditions like surcharge loads and tiered walls. Use it as a model for what to ask your own building office: how height is measured, when permits kick in, and when engineering is required.
If you’re planning a taller wall, a wall near a structure, or a wall with a driveway above it, pause and get a structural detail. That’s the line where DIY guesses get costly.
Choose Brick That Can Handle Moisture
Use brick rated for exterior use and wet conditions. Interior brick and thin veneers don’t belong in soil contact. If you’re shopping reclaimed brick, check that it’s hard-fired and not crumbly. If it scratches easily with a coin or sheds grit, leave it.
Plan The Layout So Cuts Don’t Take Over
Drive stakes at both ends and run mason’s line along the planned face. For curves, lay a garden hose to set the shape, mark the line with sand, then set stakes each few feet.
Do a quick brick count. Include extra for breaks and cuts. A buffer keeps you from mixing a new mortar batch for the last three bricks.
Tools, Materials, And Safety
What You’ll Use Most
- Shovel, trenching spade, digging bar
- Plate compactor or hand tamper
- Level (4 ft), line level, tape, square
- Brick trowel, jointer, pointing trowel
- Mason’s line, line blocks, stakes
- Brick hammer and chisel
Cutting Brick Without Breathing Dust
Brick and mortar contain silica. Cutting dry can throw fine dust into the air, so use wet cutting or a dust collection method and wear a fitted respirator if your setup calls for it. OSHA’s guidance for saw work outlines control methods tied to cutting tasks. OSHA silica dust controls for walk-behind saws is a clear reference for safe cutting habits.
Mortar Type Basics For Retaining Work
Mortar isn’t one-size-fits-all. For masonry that touches soil, specs often call for stronger mortar types than what you’d use on an indoor wall. The Brick Industry Association’s guide specs list where mortar types are commonly used, including masonry in contact with earth. Brick Industry Association mortar type recommendations is a good reference when you’re choosing a bag at the store or matching a mix design.
How To Build A Brick Garden Retaining Wall
Read the steps once, then build in order. The wall goes smoother when you don’t jump around.
Step 1: Mark The Wall Line And Dig The Trench
Set string lines to mark the face. Dig a trench wide enough for a concrete footing plus a little room to work. Dig until you hit firm soil, not loose fill. In cold regions, the footing usually goes below the local frost depth. In warm regions, you still want the footing deep enough to resist movement. If you’re unsure where the permit line sits, read how one building office frames retained height and permit triggers, then ask your local office for the matching rule. Residential retaining wall permit thresholds are a useful reference.
Step 2: Compact The Base
Rake the trench bottom flat, then compact it. If the soil is loose, add a few inches of compactable gravel, wet it lightly, and compact again. This step is boring, and it’s where straight walls are born.
Step 3: Form And Pour A Concrete Footing
Set simple forms if the trench walls won’t hold shape. Keep the footing level across its width. If the yard slopes, step the footing in level sections instead of pouring a single slanted footing.
Pour concrete, rod it with a shovel to remove air pockets, then strike it level. Let it cure at least 24 hours before laying brick.
Step 4: Dry-Set The First Course
Lay the first row of bricks with no mortar. Adjust spacing so you don’t end with a tiny cut at the end. Mark cut spots, then pull the bricks aside in order.
Step 5: Mix Mortar In Small Batches
Mix only what you can use in an hour or so. Aim for a peanut-butter feel: it should hold a trowel ridge, yet spread without tearing. Add water in small amounts. Mortar shifts fast.
Step 6: Lay The First Course Level And Straight
Spread a mortar bed on the footing, butter the end of the first brick, and tap it into place. Check level in both directions. Then set a tight mason’s line for the face and keep each brick just touching the line.
Stay consistent with joint thickness. A uniform joint is what makes brickwork look calm, even if the bricks vary slightly.
Step 7: Build Courses In A Running Bond
Stagger vertical joints by half a brick in each course. That bond ties the wall together. Check plumb on the face each few bricks and adjust while the mortar is still workable.
At this point you’ve done the parts that decide whether the wall stays true. Use this checklist to make sure you’re building a system with drainage and a protected top, not just stacking masonry.
| Component | Why It Matters | Practical Notes |
|---|---|---|
| Concrete footing | Stops settling and tipping | Wider than the wall; stepped on slopes |
| Compacted base gravel | Keeps the footing stable | Compact in lifts; avoid loose fill |
| Exterior-rated brick | Handles wet cycles | Skip soft interior brick and veneers |
| Mortar matched to exposure | Holds joints tight | Stronger types are often used near soil |
| Gravel behind the wall | Relieves water pressure | Use clean, angular stone |
| Perforated drain pipe | Carries water away | Slope to an outlet you can inspect |
| Filter fabric | Stops soil from clogging gravel | Wrap pipe in silty soils |
| Weep joints or weep tubes | Lets water exit through the face | Place low; keep openings clear |
| Cap bricks or coping | Protects the top course | Use full mortar contact and a slight overhang |
Building A Brick Garden Retaining Wall With Drainage That Works
Step 8: Install The Drainage Layer And Pipe
As you build up, place a zone of gravel behind the brick. Set perforated drain pipe at the base of that gravel zone and slope it so water can flow to daylight or to an approved outlet. If the wall sits in a low area, plan the outlet before you place pipe. A buried pipe with no exit is a clogged pipe waiting to happen.
Step 9: Add Weep Openings
Weep openings give water a direct path out. On brick walls, a common method is leaving mortar out of a head joint each few feet on the lowest course that sits above grade. Another method is setting short weep tubes and keeping them angled slightly downward.
Step 10: Tool Joints And Clean The Face
Wait until the mortar firms up, then tool joints with a jointer. Tooling compresses the joint, helps shed water, and sharpens the look. Brush off crumbs with a soft brush. If mortar smears on brick, let it firm up more, then brush again.
Finish Details That Make Brickwork Look Sharp
Keep Cuts In Low-Visibility Spots
When a run needs cuts, try to place them near the ends or where plants will break up the view. Clean cuts also matter. A wet saw gives the cleanest edge. If you use a grinder, score first, then finish the cut to reduce chipping.
Set Caps So Water Sheds Off
Cap bricks or coping keep rain from soaking the top course. Aim for a small overhang so water drips away from the face. Bed each cap in mortar with full contact so water can’t sneak into gaps under the cap.
Troubleshooting And Long-Term Care
Most wall problems show up as you build. If you catch them early, the fix is usually simple.
| What You Notice | Likely Cause | Fix While You Still Can |
|---|---|---|
| Wall starts leaning forward | Backfill placed too soon or tamped hard | Pause backfill, recheck plumb, correct the next course while mortar is green |
| Joints crack after curing | Mortar dried too fast | Mix smaller batches, shade the work, mist lightly during cure |
| White haze on bricks | Efflorescence from moisture and salts | Improve drainage, dry-brush deposits, use an approved masonry cleaner if needed |
| Weep openings spit muddy water | Soil washing into gravel | Add filter fabric, switch to clean backfill right behind the wall |
| Courses drift out of line | Line sag or inconsistent checks | Reset the line each course, keep it tight, check ends often |
| Bricks rock when set | Uneven mortar bed or debris | Lift brick, scrape bed, re-trowel mortar, reset and tap level |
| Water pools behind the wall | Outlet blocked or pipe lacks slope | Locate outlet, clear it, confirm slope, add a cleanout if reachable |
Simple Checks Each Season
- Clear leaves and mulch away from weep openings.
- After heavy rain, walk the line and look for fresh bulges or gaps.
- Touch up small voids in joints early so water can’t work its way in.
- Keep sprinklers from soaking the brick face day after day.
Final Walk-Through Before You Call It Done
Check the top line for straightness, check the face for plumb, and confirm the drainage path is clear from gravel to outlet. Let mortar cure without pressure washing. Once it’s cured, finish backfilling, grade the soil so water runs away from the back of the wall, then plant the bed and enjoy the clean edge.
References & Sources
- Montgomery County Department of Permitting Services.“Guidelines For Residential Retaining Walls.”Shows common permit triggers and how retained wall height is treated in a local building process.
- Occupational Safety and Health Administration (OSHA).“Walk-Behind Saws.”Summarizes silica dust control and respiratory requirements tied to wet cutting methods.
- Brick Industry Association.“Guide Specifications For Brick Masonry, Part 5: Mortar And Grout.”Lists mortar types and notes where stronger mortars are used, including masonry in contact with earth.