Thank you! We actually kept most of the perimeter walls and ceilings intact as they were plaster, just trenched them for new electric. You can see the before/during photos here: https://blog.leaderbuilders.com/2019/08/19/chicago-historic-renovtion.html. The exterior is stucco, so a better insulator than siding. We did replace many of the windows and exterior doors, and spray foamed the attic. Hope that helps and best of luck with your project!