What does it mean to build a new house on top of an old house and put red paper on the four corners?

The old custom is to build a new house and put red paper on the corner to ward off evil spirits and save the town. China people have a long history of advocating red. In the folk tradition of China, big red represents happiness and auspiciousness. People use red to express joy and blessing, and use red to protect themselves and eliminate disasters and exorcise evil spirits.

There are also the customs of building a house, worshiping the four corners to put copper coins, worshiping the ground and ghosts, seeking good fortune and avoiding evil, and putting red paper at the four corners, all of which can be regarded as a ceremony with a sense of security.