The century-old boiler room of The Breakers, located underground beneath the front lawn, was in danger of damage from water leaks in the ceiling. The Preservation Society undertook a major project in 2014 to excavate, repair and waterproof the roof of the boiler room, which is now open for tours.

In late 2007, a five-by-seven foot section of weakened plaster fell from the 3rd floor ceiling of the main staircase at Chateau-sur-Mer and broke into thousands of fragments, narrowly missing recently-restored light fixtures, a chair and suit of armor on the landing between the second and third floors. The collapsed ceiling included an extension of the Tree of Life that is painted on the backside of the staircase—a free-hand painted lattice interlaced with foliage and the occasional bird and butterfly. The ceiling painting dates to the 1870s renovation of the house by architect Richard Morris Hunt.

The oriental-style architectural panels in the Breakfast Room are original to the construction of The Elms. They are the room’s focal point and are enhanced by the restrained Chinoiserie detailing of the room’s sideboards. The Chinoiserie was a western interpretation of Chinese design which became popular in Europe during the late 1600s.

The dining room seat furniture at Marble House has gilded-bronze structural elements and a cut velvet textile with metallic threads. The Conservation staff is in the process of stabilizing the very degraded textile.

The gates, fences and walls of Bellevue Avenue, dating from the mid-19th to the early 20th centuries, represent the work of a number of prominent American architects. These enclosures made of brick, stone, wood andiron reflect a variety of construction methods, materials and historic revival styles. When taken as a whole, all of these gates, walls, and fences serve as a character-defining framework for Bellevue Avenue; they are the first elements an individual sees and encounters.