Retaining Walls in George — Concrete, Masonry & Engineered Solutions
Engineered retaining walls across George and the Garden Route — sized for real soil loads, reinforced correctly, drained correctly. Walls that hold, for decades.
✓ NHBRC enrolled ✓ SANS 10400 compliant ✓ Workmanship guarantee ✓ Fully insured
What We Do
The three retaining wall types we build most.
Reinforced Concrete Walls
Cast-in-place reinforced concrete retaining walls — engineered for the retained height, soil type, and surcharge loads. The structural workhorse. Formed, poured, cured, and backfilled with free-draining material.
Masonry & Block Walls
Reinforced brick or block retaining walls for lower retained heights, with engineered bond beams and reinforced cores. Often a good match for residential garden walls and level changes below 1.5m.
Gabion & Engineered Earth
Maccaferri gabion baskets for retaining in naturalistic and civil contexts — flexible, drained, and resistant to differential settlement. Also reinforced earth and MSE walls for larger civil applications.
How It Works
- Engineering first. Any retaining wall over ~1m high needs to be engineered, not guessed. We work with the structural engineer on design: wall type, thickness, reinforcement, footing, and drainage.
- Site investigation. Soil type, slope, water table, surcharge loads (building, driveway, soil above) all affect the design. We investigate and get the info the engineer needs.
- Written quote. Full itemised quote — excavation, footing, wall, reinforcement, drainage layer, weep holes, backfill, and finish. Fixed price on acceptance.
- Build with drainage. Walls hold up, drainage keeps them up. We install proper drainage behind the wall — free-draining backfill, weep holes, sub-surface drain to daylight — so water doesn’t build up hydraulic pressure.
- Certification and handover. Engineer’s certificate on completion, handover with the written workmanship guarantee, and drainage maintenance notes.
Choosing the Wall Type
A retaining wall holds back soil that would otherwise slump to its natural angle of repose. Everything else — appearance, material, cost — follows from how the wall resists that push, and there are only a handful of ways to do it.
Height usually makes the decision before preference gets a say. Low walls can be built almost any way and the choice comes down to looks and budget. As the retained height grows, the mass required by a gravity wall becomes uneconomic and you move into engineered territory — a reinforced cantilever, a properly designed gabion, or a segmental block wall with geogrid reinforcement running back into the retained soil.
Ground conditions push the choice too. On poor or settlement-prone ground a gabion often beats a rigid wall, because it can deform without cracking where mass concrete opens a crack and then keeps opening it. On a boundary where you need a vertical face and have no room behind it, a cantilever is usually the only sensible answer.
There is a fuller comparison of the four common wall types, with what each one costs you in space and excavation, in our retaining wall types compared guide.
| Wall type | How it resists | Usual height range | Suits | Trade-off |
|---|---|---|---|---|
| Gravity — mass concrete or heavy block | Sheer weight | Lower walls | Garden terracing, short banks | Wide base eats plan space |
| Cantilever reinforced concrete | Soil bearing on the footing heel | Taller walls | Boundaries, vertical faces, height | Engineered design and formwork |
| Crib — interlocking cells | Weight of the filled cells | Medium | Fast build, planted slopes | Needs a batter, cannot go vertical |
| Gabion — rock-filled baskets | Weight, and it flexes | Medium to tall, stepped | Road cuts, watercourses, poor ground | Appearance; wire life in salt air |
| Segmental block with geogrid | Reinforced soil mass behind the face | Medium to tall | Landscaped terraces, developments | Needs excavation well behind the face |
Retaining Wall Blocks — What They Can and Cannot Do
Interlocking concrete retaining blocks are the most-searched retaining wall product in South Africa, and they are genuinely good at what they are designed for. The trouble starts when they are used outside it.
Dry-stacked as a simple gravity wall, a block system works at modest heights. The blocks are set on a compacted granular levelling course, laid with the batter the manufacturer specifies, and backfilled with free-draining stone. No mortar, no footing in the conventional sense, and the whole thing relies on mass and friction.
Above that, the same blocks are used quite differently — as the facing to a reinforced soil structure, with geogrid layers laid back into compacted fill behind them at set vertical spacings. That is a different structure with a different design basis, and it needs excavation extending well behind the wall face, which is a site constraint people rarely anticipate.
Two things go wrong with block walls more than anything else. The first is stacking them higher than the system allows without the reinforcement the manufacturer’s design requires. The second is backfilling with the spoil that came out of the excavation instead of clean granular material, which turns the drainage zone into a water trap. Both look fine on the day and both show up in the second or third winter.
A planted or terraced series of low walls is frequently a better answer than one tall one, on cost, on appearance and on risk.
Drainage, Which Is What Actually Fails
Most collapsed retaining walls we are called to look at did not fail because the wall type was wrong. They failed because water built up behind them.
Saturated soil is heavier and pushes harder. Worse, water that cannot escape develops hydrostatic pressure against the back of the wall, and that load climbs quickly — it can exceed the soil pressure the wall was designed for. A wall built for dry conditions and then drowned every winter is on a countdown.
The drainage detail is unglamorous and non-negotiable: a free-draining zone of clean stone against the back of the wall, a wrapped subsoil drain at the base falling to a discharge point that actually goes somewhere, weepholes through the face at regular centres, and a geotextile separating the stone from the retained soil so the drain does not silt up within two seasons.
On the Outeniqua side of George, where winter rain is persistent rather than dramatic, the drain matters more than the wall thickness. We would rather build a slightly lighter wall with a proper drain than a heavy one discharging into nothing.
Surface water counts too. A wall with a paved area above it, or a downpipe discharging behind it, is being asked to deal with far more water than the soil alone would deliver.
Foundations, Surcharge and When You Need an Engineer
A retaining wall is only as good as what it stands on. The footing has to bear on undisturbed material or engineered fill, below topsoil and below the depth at which the ground moves seasonally.
Garden Route soils vary enormously over short distances. Sandy coastal profiles behave very differently from the clays inland of George, and low-lying erven around Wilderness and Sedgefield can carry a high winter water table that changes the design basis entirely. We dig trial holes before pricing anything structural, because founding at 600 mm and founding at 1.2 m are two quite different jobs.
Surcharge is the factor most people miss. A wall retaining a flat garden is one thing. The same wall with a driveway, a parking bay, a pool or a structure above it is carrying those loads through the soil into its back face, and it has to be designed for them.
Under SANS 10400, a retaining wall above a modest height, or any wall carrying a surcharge, requires a rational design by a competent person. That is not a formality — it is the difference between a wall that is insurable and one that is not, and it is the first thing that gets asked about if a wall ever fails. Where a design is required we bring in the engineer and build to the drawing.
Boundary walls have a second dimension: a retaining wall on or near a boundary affects your neighbour, and there are municipal requirements as well as structural ones. Worth resolving on paper before anyone digs.
Common Questions
Do retaining walls need council approval?
Over 1m retained height generally does. Over 1.5m almost always does, with engineering. We handle the plan submission and council liaison for walls that need approval.
What causes retaining walls to fail?
Almost always one of three: under-engineered for the actual load (especially if there’s building or vehicle surcharge above), no drainage behind the wall building up water pressure, or poor foundation bearing the weight. All avoidable with proper design and build.
How much does a retaining wall cost?
Per-metre cost depends on height, wall type, and access. A 1m reinforced concrete wall is roughly the same per linear metre as a medium-height garden fence — but lasts 50+ years. We quote fixed price after the site visit.
Can you build against my neighbour’s property?
Yes, but boundary walls have legal and practical implications — we’ll walk through the considerations and, where needed, advise you to discuss with the neighbour and/or the council before we start.
How high can a retaining wall be without an engineer?
Lower walls retaining nothing but a garden can generally be built as a deemed-to-satisfy solution. Once the retained height is significant, or once there is any surcharge above the wall — a driveway, a parking area, a pool or a structure — SANS 10400 requires a rational design by a competent person. Surcharge is the trigger people miss most often: a modest wall with a driveway running along the top is carrying vehicle loads into its back face and is not a garden wall any more. When in doubt we get the engineer in; the fee is small against the cost of rebuilding.
What is the cheapest type of retaining wall?
At low heights, dry-stacked interlocking blocks or a simple gravity wall are usually the cheapest built option, because they need no reinforcement design and no formwork. That advantage disappears as the height grows, because gravity walls need mass and mass needs base width, excavation and material. Compare on the whole job rather than the face area: drainage, imported granular backfill and excavation are the same on every type and are often the larger part of the number.
Do retaining walls need drainage?
Always, and it is the part most often skimped. Without a way out, water builds hydrostatic pressure against the back of the wall and adds a load the wall was very likely not designed for. The minimum is a free-draining stone zone against the wall, a wrapped subsoil drain at the base falling to a real discharge point, weepholes through the face, and a geotextile keeping the retained soil out of the drainage stone. Backfilling with the excavated spoil instead of clean granular material is the single most common way this gets undone.
What is the best retaining wall for a sloping garden?
Frequently a series of lower terraced walls rather than one tall one. Terracing reduces the retained height at each level, which usually removes the need for heavy engineering, spreads the cost, drains better and looks considerably better than a single high face. Where a single wall is unavoidable, the answer depends on the retained height, the ground and how much room there is behind the wall — which is exactly what a site visit establishes.
How long does a retaining wall last?
A correctly designed wall with functioning drainage, built on adequate foundations, is a permanent structure. What limits life in practice is water and neglect: blocked or silted drains, weepholes that have been sealed over or planted out, and surface water redirected behind the wall by later landscaping. The wire in a gabion is the exception — in coastal salt air it is the life-limiting component and the specification needs to reflect that.
Can a leaning retaining wall be repaired?
It depends what is causing the lean. A wall that is leaning, bulging in the middle of its face or showing stepped cracking through the courses is overloaded, usually by water and occasionally by a surcharge nobody planned for. Relieving the load and restoring drainage sometimes stabilises it; often the honest answer is that the structure is past repair and rebuilding to a proper design is cheaper than a sequence of interventions. We will tell you which one you are looking at rather than sell you the more expensive answer by default.
What is a gabion wall and when should you use one?
Rock-filled galvanised wire baskets, stacked and often stepped back. They are free-draining by nature, they flex rather than crack when the ground moves, and they are forgiving on poor bearing conditions — which is why they are the usual choice on road cuts, river edges and difficult ground. They are also honest about what they are; nobody mistakes a gabion for a feature wall. Near the sea, specify the wire coating for the exposure, because that is what fails first.
We Serve George and the Surrounding Towns
Based in George, building retaining walls the length of the Garden Route — residential terracing, boundary walls, driveway cuts and engineered structures.
George · Wilderness · Mossel Bay · Great Brak River · Glentana · Herolds Bay · Sedgefield · Knysna · Plettenberg Bay · Hartenbos · Oudtshoorn · Riversdale
Related pages and reading
Retaining Wall Quote
Engineered, drained, built to last. Call 073 160 7619 or book a site visit.
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