definition
strict definition
renovation start
The actual date when work began on a particular renovation campaign, separate from any forecast start date.
Renovation of a structure starts when work on it actually begins. It is a record of something that happened, unlike the expected renovation start, which holds a forecast until this date is known.
A building can be renovated many times, so this field records one campaign and not the building's history. Where several are known, each is its own event.
Renovation of an occupied building often runs in phases over years, so a start date says work began and nothing about how much of the building it reached.