C35 is one of the most widely specified structural concrete grades in the UK. It sits at the higher end of standard structural grades, offering strong load-bearing capacity without moving into specialist high-strength concrete.
If you’re planning a project that needs to handle heavy loads, harsh weather, or chemical exposure, C35 is likely on your shortlist. Working with an experienced concrete supplier ensures you get the correct mix design, strength performance, and delivery schedule to suit your specific site requirements. Here’s where it fits, where it doesn’t, and what to keep in mind when ordering.
What Is C35 Concrete?
C35 concrete achieves a compressive strength of 35 newtons per square millimetre (N/mm²) after 28 days of curing. In the European classification system, it’s designated C35/45, where 35 refers to the cylinder strength and 45 to the cube strength.
It sits above general-purpose grades like C20 and C25, and below specialist high-strength mixes like C40 and C50. That makes it a strong middle ground for projects that need more than a standard mix but don’t require ultra-high-performance engineering concrete.
Key performance traits include:
- High compressive strength that handles significant structural loads
- Strong durability against wear, weathering, and environmental stress
- Reliable chemical resistance in harsh agricultural and industrial settings
- Versatile enough for both reinforced and unreinforced applications
Main Applications of C35 Concrete
C35 is specified across a wide range of structural and heavy-duty applications. Below are the most common uses.
1. Structural Piling, Foundations, and Basements
C35 is a standard choice for foundations that support commercial buildings, multi-storey structures, and large residential developments. It provides the load-bearing capacity needed for deep strip foundations, pad foundations, and piled foundations where the ground conditions demand a stronger mix.
Common uses in this category include:
- Foundations for commercial and multi-storey buildings
- Basement slabs and below-ground structural walls
- Retaining walls under constant soil and water pressure
- Piled foundations on challenging ground conditions
2. Heavy-Duty Paving and Slabs
For external hardstanding that needs to support serious weight, C35 delivers. It’s regularly specified for loading bays, industrial yards, warehouse floors, and heavy-traffic commercial slabs where lighter grades would crack or wear down over time.
Unlike standard paving mixes, C35 holds up under repeated heavy vehicle movement and resists surface deterioration in exposed outdoor conditions. If the slab will see forklifts, HGVs, or constant machinery traffic, this is the grade to use.
Pro-Mix Concrete supplies C35 ready-mix for projects of all sizes. Whether it’s a single foundation pour or a full commercial slab, we deliver on time and to spec.
Get in touch for a free quote!
3. Reinforced Concrete Frames and Structural Elements
C35 is frequently used in reinforced concrete structures where elements carry significant loads and need long-term structural integrity. It bonds well with steel reinforcement and maintains performance over decades.
Typical structural elements include:
- Reinforced columns and beams
- Suspended and ground-bearing slabs
- Structural frames for commercial buildings
- Multi-storey car park decks and ramps
It’s a common specification in commercial construction and infrastructure projects where the structural engineer requires a proven balance of strength and workability.
4. Agricultural and Containment Structures
Agriculture is one of the most demanding environments for concrete. C35 is widely used across farm and containment builds where moisture, organic acids, and mechanical wear are constant challenges.
You’ll find C35 specified in:
- Dairy parlours and milking areas
- Silage clamps and cattle housing
- Stables, yards, and slurry stores
- Bund walls, fuel storage bases, and silos
In these applications, durability and resistance to chemical attack are just as important as strength.
When You Should (& Shouldn’t) Choose C35
C35 is the right choice when the project involves:
- Heavy structural loads
- Prolonged exposure to harsh or corrosive conditions
- Long service life with minimal maintenance
- Reinforced elements specified by a structural engineer
However, it’s not always necessary. For light domestic work like garden paths, patios, or shed bases, a C20 or C25 mix is usually sufficient and more cost-effective. On the other hand, highly specialised structural designs with extreme load requirements may call for C40 or above, typically guided by a structural engineer’s specification.
The general rule is simple: don’t over-spec where you don’t need to, and don’t under-spec where failure would be costly.
Basic Mix Info and Practical Tips
A C35 mix is designed to meet BS 8500 standards using carefully controlled proportions of cement, aggregates, and water to achieve the required 35 N/mm² strength.
The water-cement ratio is kept low to achieve the required strength, and admixtures may be added depending on the application and conditions.
On site, a few things make the difference between reaching that 35 N/mm² target and falling short:
- Compact thoroughly with a poker vibrator or tamping bar to remove trapped air
- Keep the concrete moist for at least 7 days using polythene sheeting or damp hessian
- Never add extra water on site to improve workability, as it reduces final strength
- Avoid pouring in freezing conditions or use frost protection below 3°C
- Place and finish the concrete as quickly as possible to prevent cold joints
Getting the mix right at the plant is only half the job. How it’s handled, placed, and cured on site determines whether it reaches its full potential.
Is C35 concrete suitable for domestic driveways and garages?
It can be used, but it’s often more than what’s needed. For most domestic driveways and garage floors, C25 or C30 provides enough strength at a lower cost. C35 is worth considering if the driveway will support heavy vehicles regularly.
Can I use C35 for house foundations?
Yes, C35 is commonly used for house foundations, particularly on sites with challenging ground conditions or where the structural design calls for a higher-grade mix. For standard strip foundations on stable ground, C25 is usually sufficient.
What’s the difference between C35 and PAV2?
C35 is a structural-grade concrete defined by compressive strength. PAV2 is a designated mix specifically designed for external paving exposed to freeze-thaw conditions. PAV2 includes air entrainment for frost resistance, which standard C35 does not.
Final Thoughts
C35 concrete is one of the most reliable and versatile structural grades available. From commercial foundations and reinforced frames to industrial floors and agricultural containment, it consistently delivers the strength, durability, and chemical resistance that demanding projects require.
At Pro-Mix Concrete, we make sure you get the right grade, the right volume, and the right delivery window for your project. Our C35 ready-mix is batched to BS 8500 standards and delivered by experienced operators who understand what’s at stake on site.
Want to order? Call our team or request a free quote online. We’ll have your C35 mix on site when you need it.
- Dennis Broderick is the founder and owner of Pro-Mix Concrete Company, a trusted name in ready-mix concrete solutions across the UK. With over 20 years of hands-on experience in the construction and concrete industry, Dennis brings unmatched expertise, practical insights, and a commitment to quality on every project - from residential driveways to large-scale commercial developments.
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