The Ultimate Guide to Concrete Masonry in South Africa: Costs, Standards, and Best Practices

Concrete Masonry in South Africa.

If you are planning a building project in South Africa, you are likely weighing your material choices. Among them, concrete masonry stands out as a dominant force. From affordable housing schemes to high-end commercial developments in Sandton, concrete blocks and bricks are shaping the South African landscape.

But what do you need to know about standardising, sizing, and building with concrete masonry in the local South African context? Relying on industry-standard engineering data, here is a breakdown of the costs, technical standards, and installation essentials.

What is Concrete Masonry?

In South Africa, concrete masonry refers to building walls using preformed building units of a rectangular shape. These are most commonly hollow concrete blocks or solid concrete bricks made from a mixture of cement, aggregate (such as sand, ash, or small stone particles), and water.

Unlike other materials, concrete masonry units (CMUs) are shaped and hardened using high-frequency vibration and pressure without requiring heat-intensive firing. Because they do not require massive, high-temperature kilns, concrete bricks and blocks can often be produced locally in regional block yards, dramatically cutting down on transport costs.

The fundamental difference between a concrete brick and a concrete block comes down entirely to size rather than the raw materials used. A concrete brick typically varies in length from 190 mm to 220 mm, whereas a concrete block varies in length from 300 mm up to 650 mm.

Quadra Q6 HP Vibrating Press producing concrete masonry units.

Standard Block Sizes and Compressive Strengths

The physical characteristics of concrete blocks are highly regulated in South Africa to ensure structural integrity.

Typical Sizes

While standard imperial concrete bricks generally measure 222 mm x 106 mm x 73 mm, larger hollow concrete blocks are categorised by nominal widths to match standard modular designs:

• M90 Blocks: 390mm long x 90 mm wide x 190 mm high

• M140 Blocks: 390 mm long x 140 mm wide x 190 mm high

• M190 Blocks: 390 mm long x 190 mm wide x 190 mm high

Modular co-ordination in building (following SANS 993) relies on a nominal joint thickness of 10 mm. While traditional solid concrete bricks are laid on a full-bedding face of mortar, hollow concrete blocks are laid using shell bedding along the face shells across the width of the unit, significantly optimising mortar consumption.

M90 Concrete Block

M140 Concrete Block

M190 Concrete Block

Compressive Strength Standards

The strength of the block determines where it can be legally utilised. Units are classified by their gross area compressive strength, where a solid unit contains core cavities not exceeding 25% of the gross volume, and a hollow unit contains cavities constituting between 25% and 60% of the volume. According to national standards, the baseline minimum strength for any manufactured block is 3.5 MPa, while the baseline for a concrete brick is 7.0 MPa.

South African National Standards (SANS) to Keep in Mind

In South Africa, you cannot just cast blocks in your backyard and sell them for load-bearing use. While structural rules protect built environments, the legal framework for manufacturing has unique distinctions you should know.

SANS 1215: Concrete Masonry Units

SANS 1215: Concrete Masonry Units SANS 1215 (the South African National Standard for concrete masonry units, such as bricks and blocks) is generally not a mandatory legal specification on its own. However, its application operates in a few specific ways:    

• National Building Regulations: Compliance with SANS 1215 is not universally mandated by the National Building Regulations and Building Standards Act (Act 103 of 1977). Instead, under the foundational SANS 10400-A building codes, any structural materials chosen must legally satisfy the core functional standard of being "fit for purpose."

  
  

• Ensuring Structural Consistency: This national standard governs the physical requirements, raw materials, and sampling methods for testing concrete masonry units. It acts as the benchmark to prove your blocks have uniform dimensions, minimum density, and the correct load-bearing capacity to resist environmental stress. Choosing suppliers with a verified Certification Mark ensures the concrete units are produced under acceptable, controlled factory conditions.

Nominal Concrete Brick Dimensions.

SANS 10400-K: National Building Regulations (Walls)

This part of the building regulations dictates the legal requirements for wall design, thickness, and stability. It sets out strict requirements, mapping the required minimum average compressive strength of the concrete masonry unit to its position in the building structure:

• Single-Storey Structural Walls: Require a minimum of 3.5 MPa for hollow blocks or 7.0 MPa for solid units, utilising a Class II mortar.

• Double-Storey Structural Walls: Require a minimum of 7.0 MPa for hollow blocks or 10.5 MPa to 14.0 MPa for solid units.

• Retaining Walls: Demands higher structural resistance, mandating a minimum of 7.0 MPa for hollow units and 10.5 MPa for solid units.

Pros and Cons of Concrete Masonry in South Africa

Before starting your project, it is vital to understand both the advantages and the engineering considerations of concrete block construction.

Pros:

1. Highly Cost-Efficient: Because concrete blocks are significantly larger than standard bricks, they cover walls quickly, saving on both mortar consumption and labour time.

2. Excellent Thermal and Acoustic Insulation: The hollow cores built into CMUs trap air pockets, which act as a natural barrier to heat transfer and sound.

3. Widespread Local Availability: Since raw aggregate materials are easily sourced across South Africa, concrete block manufacturers are widely distributed, keeping transport costs low.
   

Cons:

1. Moisture Movement (Drying Shrinkage): Concrete units expand and contract as they absorb and release moisture. Builders must install control joints (typically every 6 meters) to prevent cracking.

2. Required Finishing: Raw concrete blocks do not typically look aesthetically complete on their own. For residential spaces, you will need to budget for plastering and painting.

3. Permeability in Harsh Coastal Climates: Unrendered concrete can absorb dampness. In high-rainfall or coastal regions, applying a high-quality plaster and a waterproof exterior paint is highly recommended.
   

Quadra Concrete Finger Car is placing green concrete masonry blocks on curing racks.

Conclusion: Quality Masonry Starts with Quality Machinery

Building standard-compliant, durable walls in South Africa ultimately depends on the quality of the blocks you use. Even though SANS 1215 is technically voluntary, consistently meeting it is the best way for block manufacturers to prove their product is "fit for purpose" under National Building Regulations.

Achieving this standard consistently starts long before the mortar is mixed on-site—it depends on the raw engineering process. Manufacturers must carefully manage particle shapes, flaky aggregates, and grading curves (ideally targeting a Fineness Modulus of 3.2 to 4.2) to maintain proper "green strength" so that freshly moulded blocks do not distort or collapse immediately after demolding.

This is where Quadra South Africa plays a vital role. Their advanced vibrating presses (including high-performance models like the Q5E, Q6, and Q12HP) provide the precision compaction and electronic servo-controlled vibration needed to turn carefully graded aggregate blends into blocks with uniform density, clean edges, and reliable structural strength. By utilising European-engineered automation, South African concrete manufacturers can eliminate manufacturing inconsistencies, maximise aggregate performance, and reliably supply the market with premium masonry units built to stand the test of time.

References:

AfriSam, 2021. Bricks and blocks. [online] Available at: https://www.afrisam.co.za/wp-content/uploads/2021/10/55.-Bricks-and-Blocks.pdf [Accessed 7 June 2026].

South African Bureau of Standards (SABS), 2010. SANS 10400-A: National Building Regulations and Building Standards Act, 1977 (Act No. 103 of 1977): Forms 1 to 4. [online] Available at: https://www.nelsonmandelabay.gov.za/datarepository/documents/sans10400-a-forms-1-to-4.pdf [Accessed 7 June 2026]. South African Department of Public Works, 2014. PW 371-A: Construction works – General specification (Edition 2.1). [online] Available at: http://www.publicworks.gov.za/PDFs/consultants_docs/2014/PW371A_General_Specification_edition2_1Aug2014.pdf [Accessed 7 June 2026].