Every ready mix supplier sells you one of two things: concrete batched at a static plant and driven out in a rotating drum, or concrete batched at your kerb by a volumetric truck. Both can put exactly the same product in your formwork. The differences are in how you pay, how fresh it arrives, and what happens when the job doesn't match the estimate. Here's a comparison honest enough that a drum supplier could read it without wincing.
How Drum-Mixed Concrete Works
The traditional method. Materials are weighed and mixed at a batching plant, and the truck leaves the gate carrying finished concrete. The drum keeps it agitated on the road, but the chemistry doesn't pause: hydration starts the moment water meets cement at the plant. The historic British Standard guideline was to discharge within two hours of batching — that prescriptive clause was dropped in BS 8500:2023, but the Concrete Society still calls two hours a reasonable rule of thumb. It's not a law; it's prudence. Either way, drum concrete is racing a clock from the moment it's batched; ours isn't batched until it's at your site.
How a Volumetric Truck Works
A volumetric truck is a mobile batching plant. It carries the raw materials separately — sealed bins of stone, sand and cement, an onboard water tank and admixture tanks. Calibrated gates meter the materials into a mixing auger, and the concrete is blended seconds before it leaves the chute. The operator can adjust the mix, strength and slump between pours, so one visit can produce several different mixes. Billing is by metered, discharged volume: you pay for what actually goes in the ground.
The Honest Scorecard
| What matters | Drum (plant-batched) | Volumetric (mixed on site) |
|---|---|---|
| What you pay for | The load you ordered, poured or not | Metered volume actually discharged |
| Freshness | Hydrating since it left the plant — fine when the journey and the queue are short | Batched at your kerb, seconds before the pour |
| Small loads | Minimums of 2–6m³ are common, plus short-load fees of £50–£200 or per-empty-m³ charges | 0.5m³ minimum, no part-load penalty |
| Price per m³ | Indicatively £100–£150 in 2026 — can win on big, fixed volumes | Indicatively £110–£150 — usually wins on total cost for small or uncertain volumes |
| Very large continuous pours | A convoy of trucks keeps the concrete coming without a break | One truck carries materials for up to around 9m³, then reloads |
| Changing spec mid-job | One load, one mix | Switch grade or slump between pours on the same visit |
| Leftovers | Over-order and you pay for it; returned concrete is often chargeable too | Spare material stays dry in the bins — no over-order waste |
| Paperwork | Batch ticket from the plant; certified producers can supply designated mixes by name | Batch ticket printed from the truck's calibrated metering; designed mixes by strength class |
The Certification Question, Honestly
Designated mixes — the GEN, RC, PAV and FND names builders use — may only be supplied under those names by producers holding third-party product conformity certification. Many big static plants hold it, and that's a genuine advantage where a specification demands designated concrete by name.
We supply designed mixes by strength class — C20, C25, C30 and up — batched to the strength and durability requirements of BS 8500 / BS EN 206, which is entirely legitimate without certification, and every load comes with a batch ticket. When a builder asks for GEN1, we say it plainly: what builders call GEN1 is a C8/10-strength general-purpose mix, and we batch an equivalent designed mix. And if your spec strictly requires certified designated concrete — NHBC and National Highways specs do — we'll tell you so and advise, rather than fudge it.
When We'd Tell You to Use a Drum Supplier
If you're pouring 100m³ of structural concrete that can't tolerate a break, you want a big plant sending a convoy of drum trucks nose to tail. One volumetric carrying materials for roughly 8–10m³ before reloading is the wrong tool for that job, and we'd rather lose a pour than watch you order badly. The same goes for specs that strictly require certified designated mixes. There — a volumetric supplier said it in writing.
When Volumetric Wins
- Uncertain quantities. Footings never match the drawing — trenches wander and depths vary. Estimate with the concrete calculator, then relax: the meter does the exact bit, and you only pay for what's poured.
- Small loads. From 0.5m³ with no part-load fees — the economics that make our mini mix and small load service work.
- Multiple mixes in one visit. C25 footings and a C20 shed base on the same morning, from the same truck, each batched to spec.
- Tricky access. Our trucks carry extension chutes reaching around 5m — roughly double the rear reach of a typical drum mixer — which turns many "we'll have to barrow it" jobs into straight discharges.
There's more on how the truck and the metering work on our volumetric concrete page.
Get It Sorted
If your job is small, uncertain or awkward, volumetric concrete delivery is built for it — and for the sub-4m³ end, see mini mix concrete in Birmingham. Describe the pour and we'll give you a straight answer either way.