Demolition is planned take-down, and the plan is most of the value. What comes out, what stays and has to be protected, how utilities are located and cut, what the jurisdiction will require and inspect, where material goes, and how the next trade receives a clean pad or a clean shell. Done well it is quiet and quick; done casually it is the phase that produces the surprise that reshapes the rest of the job.
Selective demolition inside an occupied or partially occupied building is its own discipline. Structure has to be understood before anything is removed, temporary support and protection have to be in place, and dust, noise, and egress have to be managed for people who are still using the building. The sequence has to leave the remaining structure in a condition the next trade can actually work against.
The site issues around demolition are specific and public. Utility disconnects have their own lead times and authorities. Permits, environmental screening, and disposal requirements are not interchangeable between jurisdictions. Neighbors, access, and traffic control matter on a dense lot. These get planned up front, because a demolition that stops halfway is a very expensive place for a project to sit.
Demolition usually precedes new construction or renovation, and on larger parcels it runs alongside land clearing and land development. To have HMCM manage the work, see specialty services.