Hi Shonda,
Seeing as I have experience with historical preservation projects, one of the critical factors is the presence of records dating the building to the time of construction. If building images or property records show the time, person and occasion surrounding the construction of the building, then either the exterior (finishes, openings, etc.) or interior (fireplaces, moldings, furniture, etc.) or both would be significant and worth preserving.
If you were my client, I would ask that you obtain a report from a specialist who can study and confirm whether any features or the entire building is historically significant. That way you can be sure that anything you modified would not deface their historical value.
Finally, it is also worth noting that any addition or alterations made in a historically significant building must be a separate item part from the original building. In other words, you must provide a standalone, architecturally and structurally sound design that can stand without the support of the original building.
It is easier said than done! Let me know if you have any questions.
