Structural & Masonry Materials Used-For Guides

What Structural & Masonry Materials covers

This section covers the materials that hold buildings up and the metals used with them: bricks and blocks, brick force and reinforcement, structural steel and stainless steel, and industrial metals including chrome ore and ferrochrome.

Two quite different readerships meet here. One is building or extending something and needs to know what a material does. The other is asking about South African mining and metals — chromite, ferrochrome and related products, where the country is a major world producer and the question is genuinely about industry rather than a building site.

For the building side, the important idea is that masonry is strong in compression and weak in tension. A wall carries weight downward very well and resists being pulled apart or bent very poorly. Nearly everything else in masonry construction follows from that: reinforcement handles the tension, lintels carry loads over openings, and foundations spread weight so the ground does not settle unevenly.

Brick force is the clearest everyday example — light welded reinforcement laid in mortar joints to control cracking as a wall moves. It is not decorative and it is not optional where specified.

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How the guides in this section differ

Structural or non-structural. A wall carrying a roof and a garden wall are different problems with different requirements. The guides say which context a material belongs to.

Masonry unit type. Clay bricks, cement bricks, hollow blocks and air bricks differ in strength, thermal behaviour and purpose. Air bricks in particular exist to ventilate a space, not to carry load.

Reinforcement type. Brick force controls cracking in mortar joints. Rebar reinforces concrete. Lintels span openings. They are not substitutes for each other.

Building metal or industrial metal. Structural and stainless steel are construction materials. Chrome ore, chrome concentrate and ferrochrome are mining and metallurgy products — chromite is mined and smelted into ferrochrome, most of which goes into stainless steel production.

Material	What it does	Note
Clay or cement bricks	Load-bearing and general walling	Strength class matters structurally
Hollow blocks	Faster walling, lighter	Check load capacity before assuming
Air bricks	Ventilate underfloor and enclosed spaces	Never block them
Brick force	Controls cracking in mortar joints	Lay as specified, not occasionally
Structural steel	Beams, columns, lintels	Sized by an engineer
Stainless steel	Corrosion resistance	Several grades; coastal exposure needs a suitable one
Chrome ore / ferrochrome	Feedstock for stainless steel	Industrial, not a building material

Safety, accuracy and next-step checks

These guides are informational. Structural decisions belong to a qualified engineer, and most structural work in South Africa requires municipal approval under the National Building Regulations.

Points worth carrying:

Never remove or alter a wall without establishing whether it is load-bearing. This is the most dangerous common DIY mistake. An engineer can determine it quickly; guessing risks collapse.
Cutting masonry produces silica dust. Respirable crystalline silica causes irreversible lung disease. Cut wet or with extraction, and use a properly rated respirator — a nuisance dust mask is not adequate.
Wet cement and mortar burn skin. They are strongly alkaline and cause serious burns after prolonged contact, often with little early pain. Wear gloves, keep it out of boots, wash it off promptly.
Do not block air bricks. Blocked underfloor ventilation causes damp and timber decay. This happens routinely during renovations and paving.
Foundations and retaining walls need design. Retaining walls in particular fail dangerously and are a common source of serious incidents.
Match stainless grade to exposure. Coastal environments need a more corrosion-resistant grade; the wrong one stains and pits.
Get approval before you build. Most alterations, additions and boundary structures need municipal plan approval. Retrospective approval is harder and more expensive.
Watch for cracking patterns. Stepped cracks in mortar joints, widening cracks or doors that suddenly stick suggest movement worth investigating.

Frequently asked questions

What is brick force used for? It is light welded reinforcement laid into mortar joints to control cracking as a wall moves. It is specified at particular course intervals rather than added occasionally.

Is a hollow block as strong as a solid brick? It depends on the block and the application. Hollow blocks build faster and are lighter; load capacity varies by product and must be checked against what the wall carries.

Can I remove this wall? Not without establishing whether it is load-bearing, which needs a professional. It is the single most consequential question in domestic alterations.

What is ferrochrome used for? It is an alloy of iron and chromium produced from chrome ore, used mainly in making stainless steel. South Africa is a major producer.

Do I need plans for a garden wall? Often yes, depending on height, position and your municipality. Check before building rather than after.