Once the construction work is finished, is there anything need to do?

Since the roofs and the walls are made of blocks set in mud, trees grow out of them. This has always been a problem. To destroy the plants and trees used to be a very important event for the emperor. Every year, the emperor sent a lot of eunuchs to take out the weeds on the roofs and walls. Every year.

No nails were used in the original construction of buildings in the Forbidden City. Today, craftsmen rebuilding the Juan Qin Zai Garden must be skilled in such traditional building techniques.