Every London construction project runs on a tight schedule. Traffic restrictions, limited site access, and weather windows make concrete delivery one of the most time-sensitive decisions on any job. Ready mix concrete London suppliers deliver pre-batched concrete from a plant in a drum truck. Mix on-site (volumetric) trucks carry raw materials and batch fresh concrete at the point of pour.
Both methods are BS EN 206 certified, but they perform very differently in terms of time, cost, and waste depending on project size and complexity. The right choice depends on your volume, your schedule, and how much flexibility you actually need on the day.
Core Difference Between Ready Mix and Mix on Site?
| Factor | Ready Mix | Mix on Site (Volumetric) |
| Production | Batched at the plant, transported in a drum | Mixed fresh on site from truck bins |
| Quality control | Automated plant systems, lab tested | Real-time adjustments, operator-dependent |
| Delivery | Scheduled in one to two-hour windows | On demand, mixed when the team is ready |
| Waste | 10% to 20% over order is typical | Exact volume, you pay only for what pours |
Which Saves More Time?
Ready mix cuts placement time significantly because the concrete is ready to pour the moment the truck arrives. For large, predictable jobs like foundations, slabs, and structural frames, this speed advantage adds up fast. The trade-off is that ready mix typically requires 24 to 48 hours of booking and is vulnerable to London traffic delays that shorten the usable window before the mix starts to set.
Mix on-site eliminates the batching wait by mixing concrete on demand at the site, which means
- No wasted concrete if the pour is delayed by weather or access issues
- Ability to pause and resume without losing a load
- Faster mobilisation for small or urgent pours with no plant coordination needed
For large volume pours above 20 cubic metres, ready mix is faster overall. For smaller, variable, or weather-sensitive jobs, mixing on-site saves more time by removing the risk of wasted loads and rebooking fees.
Which Saves More Money?
Cost depends on volume, waste, and how much labour and equipment are factored in.
| Cost Factor | Ready Mix (per m3) | Mix on Site (per m3) |
| Base price | 100 to 150 pounds | 110 to 160 pounds |
| Labour and equipment | Lower (no mixing crew needed) | Higher rental but no storage costs |
| Estimated total for 50m3 | 6,000 to 8,000 pounds | 5,500 to 7,500 pounds |
Ready mix has a lower base price on large orders because plant efficiency drives the cost down at volume. Mix on-site wins on smaller jobs where over-ordering ready mix creates waste that inflates the real cost per cubic metre.
Hidden charges to watch for on both sides:
- Waiting time fees if the truck is held beyond the agreed window
- Short load surcharges on ready mix orders below the minimum volume
- Weekend and out-of-hours delivery premiums
- Pump hire costs if the site requires boom or line pump access
Advantages of Each Method
Each method has clear strengths depending on what the project demands. Here is how they compare side by side.
Ready mix strengths:
- Superior batch consistency, producing up to 40% stronger compressive results compared to on-site batching, thanks to plant controls
- Scalable for commercial volumes across multiple pours per day
- Less site clutter with no raw material storage needed
Mix on-site strengths:
- Custom adjustments to slump and admixtures on the fly during the pour
- No minimum order requirements on most volumetric suppliers
- Zero waste because you only pay for the exact volume placed
Recommended Applications
The best choice depends on project size, site access, and how predictable your schedule is.
Ready mix concrete London projects suit best:
- High rises, infrastructure, and commercial frames where consistent spec is critical
- Large volume pours above 20 cubic metres
- Sites with good access and predictable schedules
Mix on-site suits best:
- Extensions, repairs, driveways, and garden projects
- Remote or restricted access sites where drum trucks cannot reach
- Phased pours where volume is uncertain
On phased projects, contractors often use ready mix for main structural pours and volumetric mixing for smaller follow-up sections. This hybrid approach optimises cost and flexibility across the full programme.
Which Method Has the Environmental Edge?
Ready mix uses precise plant batching that reduces raw material waste and supports lower carbon mix designs. Concrete suppliers London plants are increasingly offering recycled aggregate and low-carbon cement options at a commercial scale.
Mix on-site reduces transport emissions by eliminating return trips with unused concrete. It also produces zero surplus waste on site. Both methods carry BS EN 206 certification, but plant-based labs give ready mix a slight edge on documented compliance for large commercial contracts.
Takeaway
For pours above 20 cubic metres with predictable schedules, ready mix generally saves time and reduces labour through plant efficiency and fast placement. Smaller, flexible, or weather-sensitive projects often benefit from on-site mixing, which eliminates waste and gives precise control over timing. Reviewing volumes, costs, and site access before ordering helps ensure the right choice for each job.
Many London contractors find it helpful to work with a supplier that can provide both ready mix and on-site volumetric options. Flexible delivery windows and integrated pump hire keep projects running smoothly and let teams focus on the pour rather than logistics. Pro-Mix Concrete brings over 20 years of experience supplying concrete to London projects, making it easier for contractors to get the right mix at the right time.
