Floor plans are only part of historic interior character: wall and ceiling materials, doors, woodwork, decorative plaster, stained glass, mantels and finishes are all important features. Often interiors exhibit a mix of historic styles and materials which reflect changes in use and taste. The addition of an early 20th century interior within a 19th century building, for example, is part of the building's history and worthy of preservation.
All sound and repairable interior features should be retained and repaired. If damaged or deteriorated beyond repair, the best approach is to replace the features or finishes in-kind. Another kind of interior feature-ceiling height-helps convey historic character, because it defines spatial characteristics, volume, proportion and light. Ceilings should be maintained at-or restored to-original heights.
The installation of new ceilings at lower heights is not appropriate, especially when windows, doors, archways, columns, balconies and spatial qualities are affected. Limited areas of lowered ceiling may be appropriate in secondary areas to accommodate mechanical systems, but all primary ceilings and those abutting windows should remain at full height.