A brick looks like the simplest object in construction, but the types of bricks on a building site vary widely in what they are made of, how they are made and what they are for. A fired-clay facing brick, a cement-sand common brick and a refractory firebrick share a shape and almost nothing else. Choosing the wrong one leads to staining, cracking, poor durability or a wall that cannot carry what it was meant to.
This article sorts bricks by material and by function, explains the properties that distinguish them, and covers the failure modes that matter in Singapore’s climate. How bricks are laid, bonded and combined with blocks in walls is covered in our separate guide to brickwork and blockwork.
What makes one brick different from another
Four properties define most of a brick’s behaviour.
- Compressive strength — how much load the unit can carry. It matters for load-bearing masonry and is less critical for non-structural infill.
- Water absorption — how much water the brick takes up. Low absorption indicates a dense body that resists water penetration and staining; high absorption can cause problems with mortar bond and efflorescence.
- Soluble salt content — salts within the brick or picked up from mortar and ground water migrate to the surface as the wall dries.
- Dimensional behaviour — fired-clay bricks expand slightly and irreversibly as they take up moisture after firing, while cement-based and calcium silicate bricks shrink as they dry. This governs where movement joints are needed.
Shape also matters: solid bricks, perforated bricks with vertical holes, and frogged bricks with a recess on one face all exist, and each affects weight, bond and how the brick is laid.
Types of bricks by material
Fired clay bricks
The traditional brick is made of clay or shale that is shaped, dried and fired in a kiln. Firing transforms the clay into a hard ceramic, the same process described in our sibling article on terracotta. Clay bricks can be made by extrusion and wire-cutting, by pressing into moulds, or by hand or machine moulding that produces the softer, textured faces prized in conservation work. Colour depends on the clay’s iron content, other minerals and firing conditions. Clay bricks are durable, non-combustible and colourfast, and well-fired units have very long service lives.
Cement-sand and concrete bricks
Concrete bricks are moulded from cement, sand and sometimes aggregate, then cured rather than fired. In Singapore, cement-sand bricks have long been a common choice for internal and external non-load-bearing walls in houses and flats. They are dimensionally consistent and inexpensive, but they shrink as they dry, are generally more absorbent than dense clay bricks, and rely on plaster and paint for weather protection.
Calcium silicate bricks
Also called sand-lime bricks, these are made from sand and lime pressed into shape and hardened by steam under pressure in an autoclave. They are smooth, precise and pale, and can be pigmented. Like concrete bricks, they shrink on drying and need movement joints at closer centres than clay brickwork.
Fly ash and other alternative bricks
Some bricks incorporate industrial by-products such as pulverised fuel ash or slag, reducing clay extraction and sometimes firing energy. Compressed earth blocks, stabilised with a little cement or lime and not fired, are used in some regions. Performance varies by product, so test data for strength, absorption and durability should be obtained.
Types of bricks by function
Common bricks
Common bricks are intended for walls that will be plastered or hidden. Appearance is unimportant; consistency and adequate strength are what count.
Facing bricks
Facing bricks are made for exposed walls, with controlled colour, texture and durability. They must resist weathering and staining because nothing will protect their face.
Engineering bricks
Engineering bricks are dense, strong, low-absorption clay bricks used where strength and water resistance are paramount: below ground, in damp-proof courses, retaining walls, manholes, bridges and heavily loaded piers. Their low absorption makes them resist frost and chemical attack, although they are less forgiving of poor mortar bonding.
Firebricks
Refractory bricks are made from special clays with high alumina or silica content to withstand very high temperatures. They line kilns, furnaces, fireplaces and pizza ovens. Ordinary bricks are not suitable for these uses.
Perforated, hollow and special-shaped bricks
Perforated bricks reduce weight and improve firing; hollow units offer some insulation. Special shapes such as bullnose, cant, coping and plinth bricks finish edges, sills and copings neatly and shed water.
Failure modes and how to avoid them
- Efflorescence. White salt deposits on the surface as water evaporates. Usually harmless but unsightly; persistent efflorescence signals ongoing water movement. Our guide to efflorescence explains causes and remedies.
- Cracking from movement. Shrinking concrete or calcium silicate bricks and expanding clay bricks both need movement joints. Mixing unit types in the same wall without allowing for their different movements is a common cause of cracks.
- Rain penetration. Absorbent bricks and poorly filled joints let water through solid walls; a cavity or render is often needed in exposed locations.
- Sulfate attack. Sulfates from some clay bricks or ground water can react with cement in mortar and render, causing expansion and cracking where walls stay wet.
- Spalling. Brick faces flaking off, often caused by salt crystallisation or by impervious coatings trapping moisture behind the surface.
Types of bricks in Singapore today
In the tropics, freeze-thaw damage is not a concern, which removes one of the main reasons for strict durability grading in colder climates. The local issues are rain penetration, persistent damp, salts, mould and the movement of cement-based units. Exposed facing brickwork is less common in Singapore than plastered and painted walls, though it appears on conservation shophouses, institutional buildings and some contemporary homes.
Construction methods are also changing. Lightweight blocks such as autoclaved aerated concrete, precast concrete panels, drywall partitions and prefabricated volumetric construction are increasingly used, partly because they improve buildability and reduce on-site labour, which Singapore’s planning and productivity frameworks encourage. Bricks remain common in renovation, landed housing, toilets and other areas where robustness and wet-area durability are valued.
Sustainability considerations include the high firing energy of clay bricks, cement content in concrete bricks, and transport. On the other side, well-made bricks last for generations and can be reclaimed and reused. Assessing the full life cycle, rather than the production stage alone, gives a fairer picture.
Frequently asked questions
What are the main types of bricks?
By material, the main types are fired clay, cement-sand or concrete, calcium silicate and alternative bricks using by-products or stabilised earth. By function, they include common, facing, engineering, fire and special-shaped bricks.
Are clay bricks better than cement bricks?
Each has strengths. Dense clay bricks are durable, colourfast and absorb less water, which suits exposed walls. Cement-sand bricks are consistent and economical for plastered walls but shrink as they dry and rely on finishes for protection. The right choice depends on exposure and appearance.
What is an engineering brick used for?
Engineering bricks are dense, strong, low-absorption clay bricks used below ground, in damp-proof courses, retaining walls, manholes and heavily loaded piers, where strength and resistance to water matter most.
Can a brick wall be load-bearing?
Yes, if it is designed and built as load-bearing masonry with suitable units, mortar and thickness. Many brick walls in modern framed buildings are non-load-bearing infill. Before removing or altering any wall, an engineer should confirm what it is carrying.
Related reading
- Metals in Construction: Steel, Aluminium, Copper and More
- Corten Steel in Architecture: How Weathering Steel Works
- Hardwood vs Softwood: The Real Differences Explained
- Fire Resistant Glass Door and Glazing: How Ratings Work
Unsure whether a masonry wall is carrying load before you alter it? Talk to our consultancy or get in touch.
