If your terracotta floor is becoming flaky or has white stains, it is likely that it is damaged by saline efflorescences due to rising damp. This is common with outdoors floors, where the damp due to absorption of rainwater or a poorly insulated substrate carries the salt dissolved in the water to the surface, where it becomes insoluble on contact with the air.
To clean these efflorescences, use DETERDEK or FILAPHZERO* diluted 1:5 with water, and then rinse off. If the phenomenon occurs frequently, you can apply FILAES82* anti-efflorescence protector or the water based HYDROREP ECO* ecological waterproofing treatment.
*check product availability in your market