Mainstreet Brick Business Plan — The Unit Economics of Brick Making

What a single brick costs to make and sell: cement, aggregate, labour and energy, and the cents-per-unit margin that results.

The Unit Economics of Brick Making

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Everything in this plan follows from the economics of a single unit. A concrete masonry unit is cement, aggregate, water and compaction — and cement is by far the most expensive ingredient.

Product	Ex-works price	Cement per unit	Material cost	Gross margin	Margin %
Stock brick (7 MPa)	R1.85	0.31 kg	R1.33	R0.52	28.1%
Maxi brick (90 mm)	R4.10	0.56 kg	R2.43	R1.67	40.7%
M140 hollow block	R8.60	1.15 kg	R5.18	R3.42	39.8%
M190 hollow block	R11.50	1.45 kg	R6.53	R4.97	43.2%

Figure 3. Gross margin per unit by product.

Two structural facts emerge. First, cement is roughly 43 per cent of material cost across the range, and is bought from a concentrated supplier group with limited negotiating room for a small producer. Cement price movements pass almost directly to the bottom line, which is why the sensitivity analysis in Section 15 treats cement as a primary risk rather than a routine input.

Second, the margin ranking is the inverse of the volume ranking. The stock brick — the highest-volume, most-requested product — returns 28 per cent while the M190 hollow block returns 43 per cent. The reason is geometric: a hollow block uses roughly 4.9 times the material of a stock brick but sells for 6.2 times the price, because it replaces several bricks in a wall and saves the builder mortar and labour.

2.1 The correction that matters: margin per unit of capacity

Product	Gross margin per unit	Margin %	Capacity slots consumed	Margin per 1 000 slots
Stock brick (7 MPa)	R0.52	28.1%	1.00	R520
Maxi brick (90 mm)	R1.67	40.7%	3.75	R445
M140 hollow block	R3.42	39.8%	6.43	R532
M190 hollow block	R4.97	43.2%	13.85	R359

The per-unit margin ranking reverses against the constraint that actually binds

A brick plant is constrained by machine hours, not by units. The machine produces 900 000 stock bricks a month or 140 000 M140 blocks a month — so one block consumes 6.43 stock-brick slots of capacity. Measured on that basis the M140 earns R532 per thousand brick-equivalent slots against a stock brick’s R520: an advantage of two per cent, not the fifty per cent a comparison of 40 per cent against 28 per cent implies. The maxi brick earns R445 and the M190 — the highest unit margin in the range at 43 per cent — earns R359 and is the worst use of capacity in the plant. Shifting five per cent of stock brick capacity to M140 blocks is worth roughly R6 500 a year, not the R651 000 a per-unit comparison suggests. The mix strategy is still correct, because blocks command better prices in specified work and defend against commodity pricing; but it should be pursued for margin resilience rather than as the principal profit lever, and Section 16 ranks the levers accordingly.

Figure 4. Cost structure as a percentage of revenue.

Materials alone consume roughly two-thirds of revenue, and cement alone 29 per cent. That is the defining feature of the cost structure and the reason a bulk cement supply agreement is treated as a condition precedent rather than a procurement preference.

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