Concrete Contractors in Johannesburg

A residential raft foundation in Johannesburg costs R1,200–R2,000 per square metre in 2026, depending on soil conditions, concrete strength, and reinforcing requirements. For a 120 m² home, expect to pay R144,000–R240,000 for the foundation alone. Strip foundations for boundary walls cost R800–R1,500 per linear metre. These prices include excavation, reinforcing steel, concrete, and labour. Engineer-designed drawings are additional (typically R5,000–R15,000).

Residential foundations in South Africa typically require 25 MPa concrete, which is the standard for most single and double-storey homes. Heavier structures or poor soil conditions may require 30 MPa. Your structural engineer specifies the required strength based on the building design and geotechnical report. We always pour the specified strength — never downgrade to save costs, as this compromises structural integrity and violates building regulations.

Concrete reaches approximately 70% of its design strength after 7 days and full strength after 28 days. During curing, the slab must be kept moist — we apply curing compound or wet-cure with hessian and water. You can walk on a residential slab after 24–48 hours, but do not place heavy loads or build on it until at least 7 days. Formwork for suspended slabs is typically left in place for 14–21 days.

A raft foundation is a single concrete slab that covers the entire footprint of the building — it spreads the load evenly across the ground and is ideal for weaker soils or where settlement may be uneven. A strip foundation is a narrow concrete trench that runs under the walls only — it is cheaper but requires good soil bearing capacity. Most new homes in Johannesburg use raft foundations because of the variable clay soils in Gauteng. Your engineer will recommend the appropriate type based on a soil test.

We arrange everything. We order ready-mix concrete from established batching plants (PPC, Lafarge, AfriSam) and schedule delivery to match our pour schedule. This ensures the correct mix design, strength, and slump are delivered on time. We do not use site-mixed concrete for structural work — ready-mix from a batching plant is consistent, tested, and comes with delivery dockets that confirm the specified strength for your records and building inspector.

A standard residential surface bed in Gauteng is 85–100 mm thick on a 50 mm compacted G5 sub-base, with a 250-micron polyethylene damp-proof membrane and Ref 193 weldmesh reinforcement at mid-depth — this is the SANS 10400-K and SANS 10100-2 specification for ground-supported slabs on stable founding material. Reinforced concrete driveways subject to passenger-vehicle loads should be 100–125 mm thick, increasing to 150 mm where 4x4s, bakkies or trailers are parked. Sinqobile Construction cuts expansion joints at 3–4 m intervals on every driveway pour to control thermal cracking.

Foot traffic is safe after 24–48 hours, but concrete only reaches roughly 70% of its 28-day design strength at 7 days and full strength at 28 days under SANS 10100-2 testing conditions. You can drive a passenger vehicle on a 100 mm reinforced driveway after 7 days of moist curing. Wall brickwork on a strip foundation can begin after 3–5 days. Suspended slabs and structural columns should not be loaded with permanent construction loads until 21–28 days. Sinqobile Construction applies curing compound or hessian-and-water curing on every pour for the first 7 days, the single biggest factor in achieving the specified MPa.

Ready-mix concrete is batched at a plant (PPC, AfriSam, Lafarge / Holcim) to a tested mix design with certified MPa strength, slump and aggregate-cement-water ratio, then delivered in 6 m³ truck-mixers — every load comes with a delivery docket recording the exact spec for your records and building inspector. Site-mixed concrete is mixed on the property in a pan mixer using sand, stone, cement and water proportioned by volume on site, and the strength varies pour-by-pour because measurement is approximate. Sinqobile Construction uses ready-mix exclusively for all structural pours (foundations, slabs, retaining walls, columns) and only permits site-mix for low-stress applications like garden mass concrete or fence-post backfill.