Choosing between volumetric ready-mix and DIY bagged concrete can significantly affect your project’s cost, speed and finish quality. While bagged concrete may seem cheaper at first glance, the true comparison goes beyond shelf price. Time, labour, waste and consistency all play a major role.
Volumetric ready-mix offers one clear advantage from the outset: you pay only for what you use. Concrete is mixed on site and metered precisely, eliminating the risk of over-ordering or running short.
What Does Bagged Concrete Cost?
A typical 20 kg bag of general-purpose concrete usually costs between £4 and £7, depending on brand and strength. To produce 1 cubic metre of concrete, you’ll need roughly 100 bags — around 2 tonnes of dry material, plus water.
On paper, this can look competitive. In practice, however, you must factor in:
- Mixer hire or ownership
- Labour for lifting and batching
- Time spent mixing multiple loads
- Clean-up and waste disposal
The hidden cost is time. Large pours require continuous batching to avoid cold joints, and fatigue can affect mix consistency as the day progresses.
Where Volumetric Ready-Mix Saves Money
Volumetric concrete is produced directly on site and adjusted in real time. That means:
- Exact quantities with no leftover material
- Consistent strength and slump throughout the pour
- Faster placing and finishing
- Minimal waste and packaging
Because the mix is created as you pour, you’re not racing against a drum. The supply matches your team’s pace, helping protect surface quality and reducing stress on site.
Real-World Comparisons
4m³ Driveway
A 4 cubic metre driveway would require approximately 400 bags of concrete. Even with multiple mixers, this is physically demanding and time-consuming. Maintaining consistency across that volume is challenging, and there’s a real risk of cold joints if batching falls behind.
With volumetric ready-mix, a single truck supplies a steady, consistent pour. Slump can be adjusted if weather conditions change, and you only pay for the exact metered amount delivered. For projects of this size, ready-mix almost always wins on total cost, finish quality and time efficiency.
1.5m³ Shed Base
A 1.5 cubic metre base requires around 150 bags. This is achievable for a small crew but still involves several hours of mixing and transporting concrete. If access is tight, fatigue quickly becomes a factor.
With ready-mix, the pour is completed quickly and consistently, with no leftover dry mix or packaging to handle. Once labour and time are included, ready-mix often proves better value at this scale.
Consistency and Quality Control
Bagged concrete relies on accurate water measurement and disciplined batching. As fatigue sets in, small variations can affect strength, colour and finish.
Volumetric ready-mix provides controlled, consistent output from start to finish. If temperature or wind conditions change, the mix can be adjusted immediately. This reduces the risk of defects and rework.
Waste and Clean-Up
Bagged concrete leaves empty packaging, spilled dust and often partial mixes that set before they can be used. Disposal adds both time and cost.
With volumetric supply, quantities are metered precisely, significantly reducing waste. Wash-out is managed at the truck, leaving the site cleaner and more organised.
Which Should You Choose?
Bagged concrete suits very small repairs, isolated post holes or projects where time pressure is low and spare labour is available.
Volumetric ready-mix is the stronger option when you want predictable costs, consistent quality and an efficient day on site — particularly for slabs, bases and driveways from around 0.5m³ upward. Ultimately, the cheapest option isn’t always the one with the lowest price per bag. When you factor in labour, time, finish quality and waste, ready-mix often proves to be the more cost-effective and efficient choice for most medium to large pours.