Choosing the right concrete mix for your building project is a bit like finding the perfect recipe for a cake. Too much or too little of any ingredient, and things might not turn out as planned. At Cardinalis Concrete, we’ve been helping customers across Cambridgeshire, Suffolk, Hertfordshire, Essex, and Norfolk get the right mix for over a decade. Our expert concrete delivery service in Cambridgeshire ensures your project starts with the best foundation possible.
What Is a Concrete Mix Ratio?
A concrete mix ratio is simply the amount of each material used to make concrete. Think of it as a recipe that lists how much cement, sand, and stones (called aggregate) to mix together. These ratios are usually written as three numbers with colons between them, such as 1:2:4. This means 1 part cement, 2 parts sand, and 4 parts aggregate.
Water is then added to the mix to make it workable, but too much water can weaken your concrete, so it’s important to get this right!
Common UK Concrete Mix Ratios and Their Uses
Here’s a simple guide to help you understand which mix might be right for your project:
Mix Ratio (Cement : Sand : Aggregate)
Common Name
Typical Application
Strength (MPa)
1 : 3 : 6
M10
Garden paths, slab bedding
10
1 : 2 : 4
M15
Domestic floors, footings
15
1 : 1.5 : 3
M20
Driveways, foundations
20
1 : 1 : 2
M25
Structural beams, columns
25
These ratios are recognised across the UK construction industry and follow standards like BS 8500.
How to Choose the Right Mix Ratio
1. Think About Your Project Type
For small garden projects like paths or shed bases, a lower-strength mix like 1:3:6 (M10) usually works well. For home floors or footings, a medium-strength mix like 1:2:4 (M15) is often perfect. If you’re building something that needs to bear weight, such as a support column, you’ll need a stronger mix like 1:1:2 (M25).
2. Consider Where Your Concrete Will Be
Concrete that will be outside needs to be stronger to cope with rain, frost, and general weather. For outdoor projects like driveways and patios, we usually recommend a 1:1.5:3 (M20) mix or stronger.
3. Think About Workability
Some projects need concrete that’s easier to spread and shape. Others need a stiffer mix. This often comes down to the water content, but changing the basic mix ratio can help too.
The Right Mix for Common Projects
Garden Paths and Shed Bases
Recommended mix: 1:3:6 (M10)
Why? This mix is strong enough for light use but not overly expensive.
Home Extensions and Foundations
Recommended mix: 1:1.5:3 (M20)
Why? Foundations need to be strong and durable as they support your entire building.
Driveways
Recommended mix: 1:1.5:3 (M20)
Why? Driveways need to handle the weight of vehicles and resist weather damage.
Tips for Mixing Your Own Concrete
If you’re mixing concrete yourself, here are some helpful tips:
Measure carefully: Use buckets of the same size to ensure your measurements are accurate.
Mix dry ingredients first: Thoroughly mix cement, sand, and aggregate before adding any water.
Add water gradually: Start with a small amount of water and add more as needed until the mix is workable but not soupy.
Test your mix: A good mix should hold its shape when squeezed in your hand but not be so dry that it crumbles apart.
For larger projects or when you need to ensure exact strength, it’s often better to use ready-mixed concrete from Cardinalis. Our volumetric mixers create the perfect mix on-site, so you get exactly what you need without waste.
Professional Help When You Need It
At Cardinalis Concrete, we offer concrete solutions for projects of all sizes. Our volumetric mixers allow us to create the exact mix your project needs, right there on site. This means:
No waste from ordering too much
No delays from running short
The perfect mix ratio for your specific project
Expert advice from our team of specialists
For more detailed guidance on concrete standards, the NHBC Standards – Site-mixed Concrete provides excellent information for construction projects.
Frequently Asked Questions
How much concrete will I need for my project?
To work out how much concrete you need, multiply the length × width × depth of your area in metres. This gives you the volume in cubic metres. For example, a path that is 5m long, 1m wide, and 0.1m deep will need 0.5 cubic metres of concrete.
Can I add more water to make concrete easier to work with?
While adding more water makes concrete easier to work with, it also makes it weaker. It’s best to add just enough water to make the mix workable, but not so much that it becomes soupy.
How long does concrete take to dry?
Concrete doesn’t actually “dry” – it sets through a chemical process called hydration. While concrete will be firm enough to walk on after about 24-48 hours, it continues to gain strength for weeks. Most concrete reaches about 70% of its final strength after 7 days.
Do I need to add reinforcement to my concrete?
For thin slabs or paths, reinforcement isn’t always necessary. However, for driveways, foundations, or any concrete that will bear significant weight, adding steel reinforcement (rebar or mesh) is recommended to prevent cracking and improve strength.
At Cardinalis Concrete, we pride ourselves on delivering the right concrete mix for every job. Our expert advisers are always available to help you choose the perfect mix for your project. With our decade of experience and commitment to quality, you can trust us to get it right.
For more information or to discuss your project needs, contact our team today.
