Which action must be taken before starting the demolition of a building?

Before starting the demolition of a building, obtaining a demolition permit is crucial. This permit is a legal requirement that ensures all demolition activities comply with local codes, regulations, and safety standards. The process of obtaining a permit typically involves submitting plans and specifications for the proposed demolition work to the local building department. This helps ensure that the demolition is carried out safely and responsibly, taking into account environmental considerations, structural integrity of adjacent buildings, and safety for workers and the public.

The other options may be necessary in specific situations or may represent best practices, but they do not represent the essential legal requirement that necessitates obtaining a demolition permit before any demolition work can begin.