What describes an extensive alteration of an existing structure?

An extensive alteration of an existing structure is best described as extensive renovation. This term encompasses significant changes made to a building, which could include substantial modifications to the layout, structural alterations, updates to systems (such as plumbing and electrical), and improvements that affect the building's usability or functionality. Extensive renovations are typically required when a building is being updated to meet current codes, enhance aesthetic appeal, or improve the structure's overall performance and safety.

In contrast, minor updates, cosmetic renovations, and maintenance repairs entail less invasive changes. Minor updates usually refer to small improvements that do not drastically change the existing structure or layout. Cosmetic renovations focus on surface-level aesthetics without addressing the underlying structure or systems. Maintenance repairs are generally aimed at preserving the existing condition of the building and addressing issues caused by wear and tear, rather than altering the structure significantly.