C25
The grade C25 indicates that the concrete has a characteristic compressive strength of around 25 N/mm² (when tested at 28 days) under standard conditions. It is widely used across both domestic and commercial construction because it offers a good balance of strength, durability and cost. In UK ready-mix supply this is one of the most common grades specified.
Technical details
- As per standard classification (e.g., BS?8500 / Eurocode), the “C” designation refers to concrete, and the number to strength (in N/mm²) after 28 days
- As strength increases, the mix typically uses higher cement content, reduced water/cement ratio, and optimised aggregate grading for durability. For example, typical mix ratios for conventional grades show for C25: ~398 kg cement, ~566 kg sand, ~1261 kg stone per m³
- It offers good durability for general exposure classes, assuming correct cover, curing and placementCan be used with or without reinforcement depending on structural design
Get a quote today
Our friendly staff will be able to assist you
Typical applications & key benefits
Typical applications
- Floor slabs and suspended slabs in residential and small commercial buildings
- Footings and foundations (e.g., house foundations, load-bearing walls)
- Two-storey domestic extensions
- General ground floor slabs, garage slabs, workshop floors
- Light commercial structures where loads are moderate
Key benefits
- Widely available and cost-effective given standard strength class
- Good all-round durability for typical construction exposures (non-severe)
- Simplifies logistics (many contractors/trainers familiar with C25)
- Can often be pumped and placed with common equipment
Specification & durability considerations
- Ensure the exposure class (e.g., XC, XD…) is matched to ground/ambient conditions, and that cover, reinforcement and curing are adequate
- Consider placing with slump and compaction appropriate for flooring; poor compaction or inadequate curing will reduce long-term performance
- For upper floors or structural slabs requiring reinforcement, ensure that the mix is compatible with reinforcement detailing, achieving cover and avoiding cold joints
- If aggressive ground or exposure (freeze/thaw, de-icing salts) is expected, higher class or air entrainment may be considered.
Ordering & delivery advice
Provide: slab size & thickness, reinforcement or mesh details, finish required (trowelled, floated, power?float), time to traffic, pumping requirement. Also advise if early loading is planned or if high early strength is beneficial.
