Selecting the right ready mix concrete for your project can feel overwhelming, particularly if you’re not entirely sure what all those grade numbers mean or why one mix costs more than another. Whether you’re laying a garden path in Princes Risborough or constructing a commercial development in Aylesbury, understanding concrete grades and delivery options will save you time, money, and potential headaches down the line.
At Base Concrete, we’ve been supplying ready mix concrete across Buckinghamshire for years, and we’ve seen every type of project imaginable. This guide breaks down everything you need to know about choosing the right concrete mix for your specific requirements.
Understanding Concrete Grades
Concrete grades refer to the compressive strength of the material, measured in Newtons per square millimetre (N/mm²). The most common grades range from C15 to C40, with the number indicating the strength after 28 days of curing. Here’s what each grade is typically used for:
C15 Concrete is the most basic mix, suitable for lightweight applications where structural strength isn’t critical. You’ll find this used for blinding layers beneath foundations, mass-fill work, or non-structural applications like pathways and shed bases. If you’re working on a small domestic project in Wendover—perhaps a simple garden feature or filling in around drainage—C15 is often perfectly adequate and represents the most cost-effective option.
C20 Concrete steps up the strength and is the go-to choice for most domestic applications. This is what you’d typically use for house foundations, garage floors, driveways, and internal floor slabs. Around Tring and the surrounding villages, we supply C20 for the majority of residential projects. It offers a solid balance between strength and cost, making it the workhorse of the construction industry.
C25 Concrete provides additional strength and is commonly specified for light commercial work, heavily trafficked driveways, and foundations for larger structures. If you’re undertaking a more substantial project—perhaps a commercial unit in Aylesbury or a large agricultural building—C25 gives you that extra reassurance without moving into the higher cost brackets.
C30 Concrete is where we enter commercial territory. This grade is standard for commercial concrete in London and increasingly specified for ground beams, suspended slabs, and structural elements. It’s also the minimum requirement for many highway works and areas subject to heavy loading.
C35 and C40 Concrete are high-strength mixes used in demanding applications—think multi-storey car parks, commercial foundations, construction concrete in London for larger developments, and anywhere the structural engineer has specified enhanced performance. These grades come with a higher price tag, so they’re not something you’d specify without good reason.
Factors to Consider When Choosing Your Mix
Project Type and Loading
The intended use of your concrete is the primary consideration. A garden patio has completely different requirements to a commercial warehouse floor. Be realistic about the loading your concrete will experience. Foot traffic alone? Occasional vehicles? Daily HGV movements? Each scenario demands a different approach.
Ground Conditions
The existing ground conditions in your area matter significantly. Parts of Buckinghamshire, particularly around Princes Risborough and Wendover, sit on chalk substrata which can affect foundation design. Poor ground conditions might require a stronger concrete grade or additional reinforcement to compensate. Always consult your structural engineer’s specifications if you’re working to approved plans.
Exposure Conditions
Will your concrete be exposed to the elements? Used in a marine environment? Subject to freeze-thaw cycles? Different exposure classes require specific mix designs with varying cement content and admixtures. External works around Tring, particularly those at higher elevations, can experience harsher weather conditions that might influence your choice of mix.
Project Timeline
Standard mixes typically achieve their design strength after 28 days, but rapid-hardening options are available if you need to reduce downtime. However, faster setting times require more careful planning and execution, so discuss your timeline with your supplier beforehand.
Volumetric Concrete: A Flexible Alternative
For smaller projects or sites with access challenges, volumetric concrete presents an attractive alternative to traditional barrel mixers. Volumetric mixers carry the raw materials separately—cement, aggregates, water, and admixtures—and mix the concrete on-site to your exact specifications.
This approach offers several advantages. You only pay for what you use, with no wasted concrete from over-ordering. The mix can be adjusted on-site if needed, and you can even change grades mid-pour if your project requires different strengths. For projects in the more rural areas around Princes Risborough where access might be tighter, volumetric concrete can prove invaluable.
The fresh concrete is also guaranteed—it’s mixed minutes before placement rather than during transport, ensuring optimal quality. This makes volumetric particularly popular for smaller domestic jobs where ordering a full 6m³ load isn’t practical.
Getting Your Quantity Right
Under-ordering concrete is one of the most frustrating experiences on any construction site. Cold joints between pours can compromise structural integrity, and arranging emergency deliveries causes delays and additional costs. However, over-ordering wastes money and creates disposal headaches.
Calculate your volume carefully, accounting for ground irregularities, formwork tolerances, and spillage. As a general rule, add 10% to your calculated volume for anything other than perfectly level slabs. For more complex pours—particularly foundations with irregular profiles—consider adding 15%.
Our team at Base Concrete can help verify your calculations and recommend appropriate quantities based on decades of experience supplying ready mix concrete in Aylesbury and throughout Buckinghamshire.
Local Delivery Considerations
Working with a local supplier familiar with your area offers distinct advantages. We understand the narrow lanes around Wendover, the one-way systems in Aylesbury town centre, and the access challenges on some of the more rural sites around Princes Risborough.
Delivery timing is crucial. Concrete has a limited working time, particularly in warm weather, so coordinating your workforce and site readiness with the concrete delivery prevents costly wastage. For larger pours, we can arrange multiple vehicles in sequence to maintain continuous placement.
Making Your Decision
Choosing the right ready mix concrete ultimately comes down to matching the material specification to your project requirements whilst considering practical factors like access, quantity, and budget. When in doubt, err on the side of caution—upgrading from C20 to C25 costs relatively little but provides peace of mind, whilst downgrading to save money can prove a false economy if the concrete proves inadequate.
For projects requiring building control approval or working to structural engineer’s drawings, always adhere to the specified grades—these specifications exist for good reason and aren’t areas for economy-driven compromise.
Ready to Order?
Whether you need ready mix concrete in Wendover for a domestic driveway or construction concrete in London for a major commercial project, Base Concrete provides expert advice and reliable delivery across Buckinghamshire and beyond.
Contact our team today to discuss your project requirements. We’ll help you select the appropriate concrete grade, calculate quantities accurately, and arrange delivery at a time that suits your schedule. With competitive pricing, local knowledge, and a commitment to quality, we make choosing and ordering concrete straightforward.
Get in touch with Base Concrete now to place your order or request a quote.