Understanding the Differences: Cement, Concrete, and Mortar in Construction
July 2, 2025
Cement, concrete, and mortar get mixed up constantly, and it is an easy mistake to make since all three share cement as a core ingredient. But they are not interchangeable, and using the wrong one in the wrong place is one of the more common and costly mistakes on a small building site. Here is what each one actually is, what it is used for, and why the difference matters more than most people realise.
Cement: The Binding Agent
Cement is not a building material on its own. It is the binding agent used to make both concrete and mortar. It starts as limestone and clay, which are heated together in a kiln at extremely high temperatures and then ground into a fine grey powder. On its own, cement powder mixed only with water forms a paste that shrinks and cracks badly if used in any real volume, which is why it is always combined with aggregates or sand before use.
Think of cement the way you would think of glue. It holds other materials together, but it is rarely, if ever, used by itself in a finished structure.
Concrete: The Structural Workhorse
Concrete is a composite material made from cement, coarse aggregate such as stone or gravel, sand, and water. Once mixed and cured, it becomes extremely strong under compression, which is why it is the standard choice for foundations, slabs, columns, driveways, and any structural element that needs to bear significant weight.
A typical general-purpose concrete mix in South Africa uses a ratio of roughly 1 part cement, 2 parts sand, and 4 parts stone, though the exact ratio changes depending on the strength required for the application. Foundation concrete, for example, is usually specified at a higher strength than a garden pathway.
Why Concrete Strength Matters
Getting the concrete mix wrong, particularly on a foundation, is one of the most common causes of long-term structural problems. A weak or poorly cured foundation is often the real reason a wall develops cracks or starts to lean years later, even when the brickwork above ground was done correctly.
Mortar: The Bonding Layer Between Bricks
Mortar is a paste made from cement, sand, and water, used specifically to bond bricks, blocks, or stone together and to fill the joints between them. Unlike concrete, mortar contains no coarse aggregate, which gives it a smoother, more workable consistency that a bricklayer can spread evenly and adjust while the bricks are still being placed.
Mortar is intentionally softer and more flexible than concrete. This is by design. A mortar joint needs to absorb small amounts of movement between bricks caused by temperature changes and minor settling, without transferring that stress into the bricks themselves and cracking them.
A standard mortar mix for general bricklaying in South Africa is typically around 1 part cement to 4 or 5 parts sand, though this can vary depending on the type of brick being used and local conditions.
Cement, Concrete, and Mortar Compared
| Material | Made From | Typical Ratio | Main Use |
|---|---|---|---|
| Cement | Limestone and clay, kiln-fired and ground | Not used alone | Binding agent for concrete and mortar |
| Concrete | Cement, sand, stone, water | Roughly 1:2:4 (cement:sand:stone) | Foundations, slabs, structural elements |
| Mortar | Cement, sand, water | Roughly 1:4 to 1:5 (cement:sand) | Bonding bricks and filling joints |
Why the Difference Matters on Site
Using concrete in place of mortar, or the other way around, causes real problems. Mortar used where concrete is needed will not carry structural load and can fail under the weight of a wall. Concrete used where mortar is needed sets too hard and too fast, and lacks the flexibility to accommodate the small movements a brick wall naturally experiences, which leads to cracked bricks rather than absorbed stress in the joint.
This is one of the reasons foundation work should never be treated as a place to cut corners. If you are planning a boundary wall or any structure that starts with a concrete foundation, our guide on different ways to build a boundary wall explains how foundation quality affects the wall type you choose.
Reinforcing Mortar Joints Properly
For taller or longer brick walls, mortar joints are often reinforced with brickforce, a light steel mesh laid into the joint every few courses to add tensile strength that mortar alone cannot provide. This is especially important in South African conditions where ground movement varies significantly by region. Our article on the role of brick force in construction explains why this small addition makes a big difference to long-term wall stability.
If cement or mortar residue has already dried onto the face of your bricks during construction, our guide on removing cement stains from face bricks covers how to clean it off without damaging the brick surface.
Once you understand which material you need for which part of your build, use our brick calculator to plan quantities, and browse our face brick range for your project.
Frequently Asked Questions
Can I use concrete instead of mortar to lay bricks?
No. Concrete sets too hard and does not have the flexibility mortar provides. Using it between bricks increases the risk of cracking as the wall experiences normal, minor movement over time.
What is the standard mortar mix ratio for bricklaying?
A common general-purpose mix is roughly 1 part cement to 4 or 5 parts sand, though this can vary depending on the brick type and local site conditions.
Why does concrete need stone but mortar does not?
The coarse stone aggregate in concrete gives it the compressive strength needed for structural work like foundations. Mortar does not need that strength since its job is to bond bricks, not bear structural load on its own.
Is cement the same as concrete?
No. Cement is one ingredient used to make concrete. Concrete also contains sand, stone, and water, and cannot be made from cement alone.
How long does concrete need to cure before building on it?
Concrete typically reaches enough strength to build on within about a week, but it continues gaining strength for roughly 28 days. Rushing construction before adequate curing time increases the risk of foundation problems later.
Get a Quote From Dezyno Bricks
Dezyno Bricks supplies premium clay face brick, semi-face brick, and plaster brick across South Africa from our yard in Springs, Gauteng. Call us on 061 538 5968, email sales@dezynobricks.co.za, or message us on WhatsApp to get a quote for your next project.
