Cement should be stored dry, otherwise its quality will deteriorate through premature hydration and carbonation. Moisture from air can be as harmful as direct moisture. Bagged cement that has hardened or is lumpy (as a result of being exposed to moisture) should not be used. Please store cement in a warehouse or waterproof shed and use the oldest cement first (first in, first out). Store off the floor on a wooden pallet or plastic sheeting tightly packed together. Keep doors and windows closed to eliminate airflow. Avoid contact with external walls. When storing outside, create a platform with timber slats covered in plastic sheeting on which the bags are placed. The bags must be covered with plastic sheeting to protect them from rain or water. Also create a ridge for the sheeting in order for the rain to run off instead of forming a pool. Also weigh down the edges of the cover sheeting with stones or timber to prevent it from being dislodged by wind.