How Do You Choose the Right Type of Ready Mixed Concrete?
Choosing the right concrete for your job can feel confusing. There are different grades, different mixes, and lots of technical terms. But it doesn’t have to be complicated. Here’s how to pick the right concrete for your project.
Understanding Concrete Grades
The most important thing to understand is concrete grades. These tell you how strong the concrete is.
Concrete grades have names like C20, C25, C30, and C35. The number tells you the strength. C20 means the concrete can handle 20 Newtons per square millimetre of pressure after 28 days. C35 can handle 35 Newtons per square millimetre.
Higher numbers mean stronger concrete. But stronger isn’t always better. You need to match the strength to your job.
Common Concrete Grades and Their Uses
C20 Concrete This is the weakest grade you’ll normally use. It’s fine for:
- Garden paths
- Shed bases
- Light foot traffic areas
- Non-structural work
C25 Concrete This is stronger and works well for:
- House foundations
- Garage floors
- Light driveways
- Most domestic jobs
C30 Concrete This is a good all-round choice for:
- Driveways that get regular use
- Workshop floors
- Stronger foundations
- Most commercial work
C35 Concrete This is strong concrete for:
- Heavy-duty driveways
- Industrial floors
- Structural work
- Areas with heavy loads
C40 and Above These are very strong grades for:
- Major structural work
- Heavy industrial use
- Multi-storey buildings
- Special engineering projects
How to Choose the Right Grade
Think About What Goes On Top What will your concrete need to support?
- Just people walking? C20 or C25 is fine
- Cars parking? C25 or C30 is better
- Heavy vehicles or machinery? C35 or stronger
Consider the Thickness Thicker concrete can handle more weight. If you’re pouring thin concrete, you might need a stronger grade.
Check Building Rules Some jobs have rules about what grade to use. House foundations often need C25 minimum. Check with your local building control if you’re not sure.
Ask About Ground Conditions Soft or unstable ground puts more stress on concrete. You might need a stronger grade than normal.
Special Types of Concrete
Fast-Setting Concrete This sets much quicker than normal concrete. It’s good for:
- Emergency repairs
- Jobs where you can’t wait
- Areas that need to be used quickly
But it costs more and can be harder to work with.
Waterproof Concrete This has special additives to keep water out. Use it for:
- Basements
- Retaining walls
- Areas below ground level
- Swimming pools
Fibre Concrete This has small fibres mixed in to make it tougher. It’s good for:
- Industrial floors
- Areas that get heavy use
- Places where cracking is a problem
Decorative Concrete This can be coloured or have special finishes. Use it for:
- Driveways where looks matter
- Patios and garden areas
- Decorative features
What About Workability?
Workability means how easy the concrete is to pour and finish.
High Workability This flows easily and is good for:
- Complex shapes
- Areas with lots of reinforcement
- Detailed work
Standard Workability This is fine for most normal jobs like driveways and foundations.
Low Workability This is stiffer but stronger. It’s used for structural work where strength matters more than easy pouring.
Slump Test – What Does It Mean?
You might hear about slump tests. This measures how wet and workable the concrete is.
- High slump (100-150mm): Very workable, flows easily
- Medium slump (50-100mm): Good for most jobs
- Low slump (10-50mm): Stiffer, for structural work
Most domestic jobs work well with medium slump concrete.
Questions to Ask Your Supplier
When you call for concrete, your supplier will ask questions to help choose the right type:
What’s the job? Driveway, foundation, patio, floor, etc.
How thick will it be? Thicker concrete can be a lower grade.
What loads will it carry? Cars, pedestrians, machinery, etc.
Any special needs? Waterproofing, quick setting, decorative finish, etc.
When do you need it? This affects which types are available.
Common Mistakes to Avoid
Choosing Too Strong Don’t automatically pick the strongest grade. It costs more and might be harder to work with.
Choosing Too Weak Don’t go too cheap. Weak concrete that fails will cost much more to replace.
Ignoring Conditions Weather, ground conditions, and site access all affect what concrete you need.
Not Planning Ahead Special concrete mixes might need advance notice.
Real Examples
Example 1: Home Driveway You want a driveway for two cars. Normal use, no heavy vehicles. Choose: C25 or C30 concrete, standard workability
Example 2: Workshop Floor You’re building a workshop for car repairs. Heavy tools and equipment. Choose: C30 or C35 concrete, maybe with fibres
Example 3: Garden Patio You want a patio for garden furniture and barbecues. Choose: C20 or C25 concrete, maybe decorative
Example 4: House Foundation You’re building an extension foundation. Choose: C25 minimum (check building rules), standard mix
Getting Professional Advice
Don’t guess if you’re not sure. Good concrete suppliers will help you choose the right type for your job.
Tell them:
- What you’re building
- How it will be used
- Any special requirements
- Your budget
They can recommend the best concrete for your needs.
The Cost Factor
Stronger concrete costs more, but not much more. The difference between C20 and C30 is usually small compared to your total project cost.
It’s better to spend a bit extra on the right grade than to save money and get concrete that doesn’t last.
Weather Considerations
Hot Weather You might need special additives to slow the setting time.
Cold Weather You might need additives to help the concrete cure properly.
Wet Weather You might need concrete that’s less affected by rain.
Tell your supplier about the weather conditions when you order.
Making Your Decision
Choose concrete based on:
- What the concrete needs to do
- What loads it will carry
- Any special requirements
- Building regulations
- Your budget
When in doubt, go one grade stronger rather than weaker. The extra cost is usually small, but the peace of mind is worth it.
Working with Express Concrete
At Express Concrete, we help customers choose the right concrete every day. We ask the right questions to understand your job, then recommend the best concrete for your needs.
We keep all common grades in stock, and we can arrange special mixes when needed. Our experience helps you get exactly what you need without paying for more than necessary.
Don’t worry if you’re not sure what concrete you need. That’s what we’re here for. Just tell us about your project, and we’ll help you choose the right type.
The right concrete makes all the difference to your finished job. Take time to get this choice right, and your project will last for years to come.