What Strength Concrete Do I Need? A Simple Guide to C20, C25, C30 & C35 Concrete
- Admin
- Jun 15
- 3 min read
Choosing the right concrete strength is one of the most common questions we’re asked at William The Concreter.
Whether you're laying foundations for an extension, installing a new driveway, building a garage base or working on a commercial project, using the correct concrete mix is essential to ensure your project is safe, durable and built to last.
In this guide, we'll be explaining the most common concrete strength grades, what they're used for, and how to choose the right one for your project.
What Does C20, C25, C30 and C35 Mean?
Concrete strength is measured by how much pressure it can withstand after it has fully cured (typically after 28 days).
The letter 'C' simply stands for Concrete, while the number refers to its compressive strength measured in megapascals (MPa).
As a general rule, the higher the number, the stronger and more durable the concrete.
However, stronger isn't always better. Choosing the correct strength for your project is more important than simply selecting the highest grade.
C20 Concrete
C20 concrete is commonly used for lighter domestic projects where heavy vehicle traffic isn't expected.
Typical uses include:
Garden paths
Shed bases
Greenhouse bases
Internal floor slabs
Domestic footpaths
For many smaller DIY projects, C20 provides an excellent balance between strength and value.
C25 Concrete
C25 is one of the UK's most commonly used concrete grades for domestic construction.
It's suitable for:
House foundations
Garage bases
Patio bases
Ground floor slabs
Lightly trafficked driveways
Many home extension projects throughout East Sussex and Kent use C25 concrete for foundations due to its excellent structural performance.
C30 Concrete
C30 offers greater durability and is often specified where the concrete will experience heavier loads or more demanding conditions.
It's commonly used for:
Domestic driveways
Workshop floors
Agricultural buildings
Larger foundations
Commercial flooring
If you're regularly parking cars or vans on a new concrete driveway, C30 is often an excellent choice.
C35 Concrete
C35 is designed for more demanding structural and commercial applications.
Typical uses include:
Commercial yards
Heavy vehicle areas
Industrial flooring
Structural reinforced concrete
Its higher strength makes it suitable where increased durability and long-term performance are essential.
Which Concrete Strength Do I Actually Need?
Every project is different.
The right concrete strength depends on factors such as:
What you're building
How much weight the concrete will carry
Ground conditions
Whether reinforcement is being used
Your engineer's or builder's specification
If you're unsure, don't worry.
At William The Concreter, we help homeowners, builders and contractors choose the correct mix every day. We'll happily discuss your project and recommend the most suitable concrete for your requirements.
Why Choosing the Right Mix Matters
Using the correct concrete isn't just about strength.
The right mix helps ensure:
Long-term durability
Reduced risk of cracking
Better resistance to weather
Improved structural performance
Compliance with building requirements
Ordering a stronger mix than necessary isn't always the most cost-effective solution, while choosing a mix that's too weak could lead to expensive problems later.
That's why professional advice is always worthwhile.
Ready-Mix Concrete Delivered Across East Sussex & Kent
William The Concreter supplies high-quality ready-mix concrete for domestic, commercial and agricultural projects across:
Hastings
Battle
Bexhill
Rye
Eastbourne
Tunbridge Wells
East Sussex
West Sussex
Kent
Whether you're building a house extension, laying foundations, installing a new driveway or completing a commercial development, we can supply the correct concrete for your project.
Need Advice? We're Happy to Help.
If you're unsure which concrete strength you need, simply get in touch with our friendly team.
We'll discuss your project, recommend the most appropriate mix and arrange delivery at a time that suits you.
You can also use our Concrete Calculator to estimate how much concrete your project requires before ordering.
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