Precast Wall Calculator, South Africa
Work out panels, posts and cost for any precast concrete (Vibracrete) boundary wall, with a supply-only breakdown and an installed-cost cross-check.
Quick answer: A standard precast wall uses panels 1,440mm long by 300mm high, stacked between posts set at 1.5m centres, so a 1.8m wall needs six panels per bay. Supply-only material (panels and posts) costs meaningfully less than a professionally installed wall, which runs approximately R620–R1,400 per linear metre in 2026 depending on finish and height.
⚠️ For planning purposes only. Confirm exact panel and post pricing with your chosen supplier before ordering.
How to Use This Calculator
Enter your wall length in metres and select your wall height. Panels come in fixed 300mm increments, so height is picked from the four standard sizes (1.8m, 2.1m, 2.4m or 2.7m) rather than typed freely. Then choose your panel finish: plain or brick-line panels are the most affordable, pebble-dash adds texture, and decorative double-pattern costs the most.
Enter the combined width of any gate openings to deduct from the total run. Results show your exact panel and post count, plus a supply-only cost estimate and an installed-cost cross-check so you can compare DIY material cost against a professional quote.
Precast walls in South Africa: what you're actually buying
A precast concrete wall, commonly called "Vibracrete" in everyday SA usage, is built from factory-cast concrete panels stacked between posts, not laid brick by brick on site. Standard panels measure approximately 1,440mm long by 300mm high, so wall height comes in 300mm steps: six panels for a 1.8m wall, seven for 2.1m, eight for 2.4m and nine for 2.7m. Posts are set at 1.5m centres and typically run about 600mm below ground regardless of wall height, so a 1.8m wall needs a post roughly 2.4m long overall.
Getting your panel and post count right before calling a supplier gives you a real number to check quotes against, the same reason our Boundary Wall Calculator exists for brick walls. Most precast suppliers quote a blended price per metre installed. This calculator instead itemises panels and posts separately, so you can see exactly what you're paying for.
SA precast wall panel finishes compared
| Finish | Price per Panel | Look | Best Use |
|---|---|---|---|
| Plain / brick-line | ~R65–R67 | Smooth or brick-textured face | Budget boundary walls, rented or resale properties |
| Pebble-dash / textured | ~R119–R155 | Exposed aggregate texture | Mid-range residential, better weathering appearance |
| Decorative / double-pattern | ~R230 | Moulded pattern, two-sided finish | Street-facing walls, premium finish |
Precast wall formula
Net wall length = Total length − Gate openings
Bays (post sections) = CEIL(Net length ÷ 1.5)
Posts = Bays + 1
Panels = Bays × Panels per bay (height-dependent)
Post length = Wall height + 0.6m embedment
Do you need council approval for a precast wall?
SANS 10400 Part A's minor building work exemption covers a freestanding wall up to 1.8m high that doesn't retain soil, precast included, so plans don't need to be submitted or approved for a standard-height boundary wall. Above 1.8m, precast is different from brick in an important way: there's no public SANS deemed-to-satisfy table setting post spacing or panel limits the way SANS 10400-K's pier table does for masonry walls. A taller precast wall's structural adequacy instead rests on the manufacturer's own engineering certification against SANS 10160-3 wind loading, not a spacing rule you can look up yourself. Always confirm your specific municipality's requirements, and get written engineering sign-off from your supplier for anything above 1.8m.
Precast (Vibracrete) vs brick: which boundary wall is right for you?
Quick answer: Precast installs faster and generally costs less upfront, R620–R1,400 per metre installed against a plastered single-skin brick wall's R1,800–R2,800/m. Brick lasts longer, 50-plus years against precast's 20 to 35, and insulates sound better.
| Precast Concrete | Single-Skin Brick | |
|---|---|---|
| Installed cost (2026) | R620–R1,400/m | R1,800–R2,800/m |
| DIY material cost only | See this calculator's supply estimate | R600–R900/m |
| Install speed | 20–30m/day | 6–10m/day |
| Lifespan | 20–35 years | 50+ years |
| Sound insulation | Moderate | Better, especially double-skin |
| Council approval | Same 1.8m minor-work threshold as brick, no public spacing table above it | SANS 10400-K pier table above 1.2m |
Building costs generally, and how brick and precast fit into a full construction budget, are covered in more depth in our Building & Developer Costs topic hub. If you already know you want brick, run the numbers on our Boundary Wall Calculator instead. It covers single-skin, double-skin and pillared brick configurations with the same itemised approach used here. For a wider read on both options with provincial labour rates, see our Boundary Wall Cost Guide.
Can you raise or extend an existing Vibracrete wall?
Yes, and it's one of the more common questions people search before calling a supplier. Extending a precast wall along a new run means adding more post-and-panel bays at the same 1.5m spacing, ideally matched to your existing finish. Raising an existing wall's height means stacking extra panels on top of the current run inside the same posts, but only if those posts were originally set long enough to take the extra weight and height, and if your original panel finish is still available. Before committing to either, check panel availability with a supplier: some finishes get discontinued, and a mismatched replacement panel is more visible on a low wall than a high one.
A worked example: 30m wall at 1.8m with plain panels
Take a 30-metre precast wall at the standard 1.8m height, no gate openings, using plain panels. At 1.5m post centres, 30m needs 20 bays (CEIL(30 ÷ 1.5)) and 21 posts. Six panels per bay at 1.8m gives 120 panels in total. At approximately R66 per plain panel, that's R7,920 in panels; at approximately R265 per standard post, that's R5,565 in posts, for a combined supply cost of roughly R13,485 before any price variation. Allowing for the typical range between suppliers, budget R12,137–R15,508 for panels and posts alone. Cross-checked against the R620–R1,400/m professionally installed range, a 30m wall like this would cost roughly R18,600–R42,000 fully installed. The gap between that figure and the supply-only estimate is post-hole concrete, excavation and labour. Posts for this wall need to be about 2.4m long overall (1.8m wall height plus 0.6m embedment), worth confirming with your supplier before ordering, since a post cut short at the yard is a much harder problem to fix once it's set in concrete.