What term is used for the restoration of a property to its former or improved condition without altering its basic design?

The term that accurately describes the restoration of a property to its former or improved condition without altering its basic design is "restoration." This process involves carefully repairing and renewing structures to return them to their original state while maintaining the architectural integrity and historical significance of the building. Restoration is often based on historical records, previous designs, or photographs to achieve a specific look that reflects the original design or character of the property.

While terms such as renovation and rehabilitation might suggest improvement or updating of the property, they tend to imply changes in design or functionality, rather than a strict return to an original state. Reconstruction usually refers to building something again that may be destroyed or not existing anymore, which does not fit the context of maintaining the existing design. Thus, "restoration" is the most precise term for this process.