Concrete Drying Time Estimator — Curing Stages and Timelines

This estimator calculates approximate drying and curing times based on slab thickness, ambient temperature, humidity level, and concrete type. It uses the industry-standard rule of approximately 1mm per day drying rate at 20°C and adjusts for conditions.

Curing stages

• Initial set (2-6 hours): Concrete stiffens and cannot be worked. Do not disturb.
• Walkable (24-48 hours): Safe for light foot traffic only.
• Light load (3-7 days): Can begin building on the concrete. Remove formwork.
• Full cure (28 days): Concrete reaches design strength (e.g. C25/30).
• Fully dry (for floor finishes): Typically 1mm per day — a 100mm slab takes ~100 days.

Adjustment factors

• Temperature: Below 10°C slows curing significantly. Below 5°C, concrete can be damaged by frost. Above 30°C accelerates setting but increases cracking risk.
• Humidity: High humidity slows drying. Low humidity speeds it but can cause surface cracking.
• Concrete type: Rapid-set concrete cures up to 40% faster than standard OPC concrete.

Standards reference

Curing guidance aligns with BS 8110 and Eurocode 2 (BS EN 1992). Drying times for floor finishes follow BS 8203 (Installation of resilient floor coverings) and BS 8204 (Screeds, bases, and in-situ floorings). Always verify moisture levels with appropriate testing before applying floor coverings.