A built object is under construction when its original form is actively taking shape, when an addition belonging to it is being built, or when construction work has been paused. The construction phase begins when foundation work begins and ends with the object's completion. The first physical elements belonging to the structure must be put in place when this status takes effect - therefore excavation and site cleanup do not normally signal the beginning of construction.

When an object's basic form is completed it is considered to be topped out; however it remains under construction until all major design elements are completed and the object is ready for use.

Prefabrication of structural elements off-site is not considered an indicator of construction, unless the entire structure is prefabricated in one place and moved to another place.

If a structure incorporates minor pieces or surface elements of a partly demolished structure from its site, construction begins only when the first new elements are put into place. In other words, construction is not indicated merely by the existence of elements which are to be recycled into the new structure. If the recycled elements constitute the structural framework, then the old structure and the new structure are generally to be considered different stages of the same structure, and construction is said to begin anew when newer elements are added to the old.