AEC & BIM Knowledgebase Error Solution Guide Single Footings Single Footings The messages that appear in the single footing controls and their possible solutions are listed under this heading. Insufficient reinforcement on single footing Ground Safety On Single Footing Negative Single footing size cannot be less than 70 cm. Single footing area cannot be less than 1m². Single footing thickness cannot be less than 25 cm. Single footing thickness cannot be less than 1/4 of the cantilever opening. Next TopicInsufficient reinforcement on single footing ×