How long can unused mortar be kept before it should be discarded?

The correct timeframe for discarding unused mortar is 2 1/2 hours. This guideline is essential for maintaining the integrity and performance of the mortar during construction. After this period, the mortar begins to harden due to hydration, making it difficult or impossible to work with effectively.

Using mortar that has passed this timeframe can lead to compromised strength and bonding capabilities, which are critical for the success of masonry work. Hence, the 2 1/2 hour mark ensures that the material remains workable and retains its intended properties for bonding masonry units. Adhering to this guideline helps builders avoid costly mistakes and ensures the quality of their work remains high.