Serving as a third-party impartial unit. Before the construction of the structure, perform current status appraisal on the buildings within the affected area around the base area. The content includes plan drawing, original structure crack record, leveling measurement, tilt measurement, plan writing In the end, it is written into a report, which has legal benefits, and is used by the construction unit as an exhibit to prevent neighbor damage during or after construction, and to clarify the responsibility of the evidence.