AI agents for business finance: what they can and can't do
What AI agents can do in bookkeeping, close, collections and compliance today, where a person must stay in charge, and how to judge a product.
The short answer
You can start making interlocking paving stones with plastic or rubber moulds and a vibrating table, then move to a hydraulic or vibro-compaction machine once orders justify it. In our labelled example, a 20 square metre batch costs ₦128,000, about ₦6,400 per sqm, and sells for supply only at ₦8,500 per sqm, leaving ₦42,000 before rent and equipment wear. Cement is the cost that moves most, so recost every order.
How interlocking paving stones are made
Interlocking stones are concrete units shaped so they lock together when laid on a compacted base with sand joints. Clients use them for compounds, driveways, estate roads, filling stations and church and school grounds. The product is cement, sand and fine aggregate pressed or vibrated into a shape and cured until hard. The two things buyers judge are strength (no cracking or crumbling under cars) and finish (even colour, clean edges).
Moulds versus machine
| Manual moulds and vibrating table | Block or paver machine | |
|---|---|---|
| How it works | Wet mix poured into plastic or rubber moulds, vibrated, left to set, then demoulded | Semi-dry mix compacted and vibrated under pressure, stones pushed out on pallets |
| Start-up cost | Low: moulds, vibrating table, mixer or shovels | Higher: machine, often diesel or three-phase power, pallets |
| Finish | Smooth, glossy faces; colour shows well | More uniform size; usually stronger at the same cement content |
| Output | Limited by number of moulds and curing space | Much higher per day |
| Labour | More handling and demoulding | Fewer hands per stone, but skilled operator needed |
Many businesses start with moulds for decorative jobs and add a machine when they win estate or commercial contracts. Price machines by output per day, the cost of extra mould sets for different shapes, power needs, and whether the dealer will train your operator. We did not find a reliable published price list for paver machines in Nigeria as at October 2026, so collect written quotes.
Materials and mix
- Cement: the main cost and the main source of strength. Skimping on cement is the commonest cause of stones that crumble. See today's cement price.
- Sharp sand and stone dust or granite chippings: clean, free of clay and organic matter.
- Water: clean; too much weakens the stone.
- Pigment: red, black, yellow and others; add consistently so batches match.
- Release oil for moulds and plasticiser if you use one.
Get your mix design from a trained builder or concrete technologist and test it. Break a few stones from each early batch to see how they hold up, and keep a record of mix, water and curing for every batch.
Worked example: a 20 sqm batch (example figures)
Example only. We assume 5 bags of cement make 20 sqm of 60mm stones for this mix, and use illustrative prices. Your yield depends on your mix and stone thickness.
| Cost line (example) | Amount |
|---|---|
| 5 bags of cement at ₦10,000 | ₦50,000 |
| Sharp sand and stone dust | ₦30,000 |
| Pigment | ₦8,000 |
| Water | ₦2,000 |
| Labour | ₦25,000 |
| Power or diesel for vibrating table | ₦8,000 |
| Release oil and mould wear | ₦5,000 |
| Total for 20 sqm | ₦128,000 |
Cost per sqm: ₦128,000 ÷ 20 = ₦6,400. At a supply-only price of ₦8,500 per sqm, 20 sqm brings ₦170,000 and leaves ₦42,000 before rent, delivery and equipment wear. A rectangular 200mm by 100mm stone covers 0.02 sqm, so a square metre takes about 50 of them; use that to plan mould sets and curing space.
Pricing per square metre: supply versus supply-and-lay
Quote supply-only and supply-and-lay separately. Laying adds excavation, base material (laterite or stone base), compaction, kerbs, edge restraint, sand for joints, labour and transport. Clients often compare only the headline price per sqm, so list what is included. Charge delivery by distance and truckload, and charge kerbs per metre.
- Measure the site and add a waste allowance for cuts at edges.
- Price stones per sqm from your batch cost plus margin.
- Price base preparation and laying per sqm.
- Add kerbs per metre and delivery per trip.
- State validity: cement prices change, so keep quotes short-dated.
Your first jobs usually come from builders, estate managers and churches who can see finished work. Lay a sample area at your yard so clients can walk on it and compare colours.
Curing, storage and quality
Stones gain strength over time. Keep them shaded and damp for the first days after demoulding so they do not dry too fast and crack, and do not deliver green stones that are still weak. Stack on pallets in a level yard. A larger yard lets you hold stock for big orders, which wins contracts. The Standards Organisation of Nigeria's MANCAP scheme lists civil, building and mining among the sectors where locally made products must meet Nigerian Industrial Standards; ask SON whether your product line needs certification, especially before bidding for public or estate contracts.
Where Pryme fits
Register the business (CAC's 29 May 2025 schedule lists ₦20,000 for a business name, plus ₦1,000 for name reservation) and take deposits by transfer into a Pryme Business Account. Invoicing handles deposit and balance. For related pricing, see pricing a gate and what a new customer costs.
Questions people ask
How much is interlocking stone per square metre in Nigeria?
It varies by thickness, colour, cement price and whether laying is included. In our labelled example, production costs ₦6,400 per sqm and supply-only sells at ₦8,500.
How many interlocking stones make one square metre?
For rectangular 200mm by 100mm stones, about 50. Other shapes differ; check your mould size.
Which is better, interlocking mould or machine?
Moulds cost less to start and give a glossy finish; machines produce more, more uniformly. Many start with moulds and add a machine later.
How many bags of cement for interlocking?
It depends on your mix and thickness. Our example assumes 5 bags for 20 sqm of 60mm stones; test your own mix.
Sources
- Mandatory Conformity Assessment Programme (MANCAP), Standards Organisation of Nigeria · accessed Oct 2026
- CAC New Schedule of Fees, Corporate Affairs Commission, 29 May 2025 · accessed Oct 2026
This article is general information, not financial, legal or tax advice. Products described are provided under the terms on this site and are subject to regulation and eligibility.