For homeowners and DIY enthusiasts embarking on concrete projects, the question of whether to mix concrete themselves or order ready-mix delivery is often driven by budget considerations. At first glance, buying bags of cement, sand, and aggregate separately appears significantly cheaper than ordering from a concrete supplier. However, the true cost comparison is considerably more complex than it initially seems.
The Apparent Cost Advantage of DIY Mixing
When you browse the aisles of a builders’ merchant, pre-mixed concrete bags or individual components seem reasonably priced. A 25kg bag of cement costs around £5-8, sand is relatively inexpensive, and aggregate can be purchased in bulk bags. For very small projects requiring less than 0.25 cubic metres of concrete, mixing your own can indeed be the more economical option.
This approach works well for setting fence posts, creating small garden features, minor repairs, or filling small holes. When you only need a few dozen litres of concrete, buying several bags makes practical and financial sense.
The Hidden Costs of Mixing Your Own
However, as project size increases, numerous hidden costs begin to erode or eliminate any apparent savings from DIY mixing.
Time and Labour
Mixing concrete manually is extraordinarily time-consuming and physically demanding. A cubic metre of concrete weighs approximately 2,400 kilograms. Even with a small cement mixer, you’ll need to measure, load, mix, and transport dozens of individual batches. What a ready-mix lorry delivers in minutes might take you an entire day or more to mix manually.
Your time has value, even on a DIY project. If you’re taking time off work or sacrificing a weekend, that represents a real cost that should factor into your calculations.
Equipment Requirements
Unless you already own a cement mixer, you’ll need to hire one for larger projects. Mixer hire typically costs £30-60 per day for a basic model, with more robust machines costing considerably more. You’ll also need wheelbarrows, shovels, buckets for measuring, and protective equipment.
For substantial projects, you may need to hire a mixer for multiple days, with costs mounting quickly. Additionally, you’ll need suitable transport to collect hire equipment and return it, potentially requiring a van hire if you don’t have appropriate vehicles.
Material Transportation
Cement, sand, and aggregate are extremely heavy. A single bulk bag of sand weighs approximately 850kg, whilst aggregate bags are similar. Unless you have a suitable vehicle with adequate load capacity, you’ll need multiple trips to collect materials or pay for delivery charges that can be substantial.
Many builders’ merchants charge £50-100 for delivering materials, particularly if you’re in a less accessible location or require multiple bulk bags. These delivery fees quickly add up and must be factored into your cost comparison.
Consistency and Quality Concerns
Achieving consistent concrete strength and quality when mixing manually is challenging. Professional ready-mix concrete is batched to precise specifications with computerised controls ensuring exact proportions. When mixing by hand or with a small mixer, achieving the correct ratios consistently across multiple batches is difficult.
Incorrect ratios can result in weak concrete that fails prematurely, ultimately costing far more to repair or replace than any initial savings. One batch slightly too wet, another too dry, and you’ll have inconsistent results that may compromise structural integrity.
Wastage
When ordering materials separately, accurately calculating quantities is difficult. Most DIYers overestimate and end up with leftover materials, or underestimate and need to make additional trips. Ready-mix suppliers calculate exact volumes needed, minimising wastage.
Partially used cement bags that get damp are unusable. Leftover aggregate and sand need storage space and often go to waste, representing money spent on materials you never use.
Physical Toll
The physical demands of mixing concrete shouldn’t be underestimated. Back injuries, muscle strain, and exhaustion are real risks when handling tonnes of heavy materials. The physical toll, whilst not directly monetary, represents a significant hidden cost.
When DIY Mixing Makes Financial Sense
Despite these drawbacks, situations exist where mixing your own concrete remains the most cost-effective option:
Very Small Projects
For projects requiring less than 0.1 cubic metres (roughly 5-6 standard wheelbarrow loads), buying bags of pre-mixed concrete or mixing small batches often costs less than minimum delivery charges from ready-mix suppliers.
Remote Locations
If your project is in a location where ready-mix lorries cannot access or where delivery charges are prohibitively expensive, DIY mixing might be your only practical option.
Non-Structural Applications
For decorative work, garden projects, or applications where structural integrity isn’t critical, the quality consistency concerns matter less, making DIY mixing more viable.
Multiple Small Pours Over Time
If you’re undertaking several small projects spread over weeks or months, keeping materials on hand and mixing as needed can be more practical than scheduling multiple ready-mix deliveries.
Projects Under 0.5 Cubic Metres with Existing Equipment
If you already own a decent cement mixer and have suitable transport, projects requiring up to half a cubic metre might still be economically mixed yourself, particularly if you value the flexibility of working at your own pace.
When Ready-Mix Is the Better Value
For most projects over 0.5 cubic metres, ready-mix concrete typically proves more economical when all factors are considered:
Time Savings
A ready-mix lorry can discharge a cubic metre of concrete in minutes. This speed is impossible to match with manual mixing and is particularly crucial for larger pours where concrete needs to be placed before initial setting begins.
Labour Efficiency
Rather than spending hours mixing, you and any helpers can focus entirely on placing and finishing the concrete. This efficiency often means completing the entire project in one session rather than spreading it over multiple days.
Guaranteed Quality
Professional ready-mix is batched to specified strength grades with quality controls that DIY mixing cannot match. For structural applications like foundations, driveways, or garage bases, this quality assurance is invaluable.
No Equipment Hire or Material Delivery Charges
The price you pay for ready-mix includes delivery directly to your pour location. You avoid separate charges for mixer hire, multiple material deliveries, and equipment transport.
Reduced Physical Strain
Professional delivery eliminates the back-breaking work of manual mixing, reducing injury risk and allowing you to remain fresh for the actual placing and finishing work.
The Break-Even Point
For most domestic projects, the break-even point where ready-mix becomes more economical than DIY mixing typically occurs around 0.5 to 1 cubic metre. Below this volume, especially for non-critical applications, DIY mixing might save money. Above this volume, ready-mix almost always proves more cost-effective when all factors are considered.
Additional Considerations
Project Timeline
If you need concrete quickly or have weather concerns, ready-mix delivery allows you to complete the work in optimal conditions rather than spending days mixing with changing weather potentially compromising your work.
Inspection Requirements
For projects requiring building control inspections, inspectors often want to see delivery tickets confirming concrete strength grades. DIY mixed concrete lacks this documentation, potentially complicating approval processes.
Insurance Implications
For commercial work or projects affecting property structure, using certified ready-mix concrete may be necessary for insurance purposes or compliance with building regulations.
Making the Right Choice
The decision ultimately depends on your specific circumstances. Consider the total project volume, your available time and physical capability, whether you have necessary equipment, and the structural importance of the work.
At National Mini Mix, we understand that every project has unique requirements and budget considerations. We offer flexible delivery options including small loads that make ready-mix concrete accessible even for modest projects where the convenience, quality, and time savings can outweigh any marginal cost differences.
Conclusion
Whilst mixing your own concrete can be cheaper for very small projects, the apparent savings diminish rapidly as project size increases. Hidden costs including time, labour, equipment hire, transport, and potential quality issues often make ready-mix concrete the more economical choice for anything beyond minor repairs or small decorative work.
Rather than focusing solely on material costs, consider the total investment including your time, physical effort, and the assurance of quality results. For most concrete projects, professional ready-mix delivery provides better value, superior consistency, and significantly less hassle than mixing your own.
