Greater Whitehall
Pediment Restoration
17 Battery Place
Written By Casey Bolles & Zach Daddis
December 30, 2024
Scaffold removed from the facade of the Whitehall Building
Project Description
Scope & Context of this Multi-Year
Historic Restoration
At the southern tip of NYC’s financial district, across the street from Battery Park, looms a nearly 450’ tall masonry structure adorned with terracotta and limestone, now a host to around 500 sqft. of GFRC (Glass Fiber Reinforced Concrete), totaling at over 300 individual pieces. You can’t tell that by simply looking, however. From street level or even from right on the rooftop, the sculptural parapet still appears to be the original limestone, which is a sign of a restoration expertly executed.
The Whitehall Building is a definitive example of Renaissance Revival Architecture, designed by Henry Janeway Hardenbergh, built in 1904 and totaling 20 stories. 1910 marked the addition and construction of a massive 31-story additional annex designed by the architecture firm Clinton and Russel. Popularly referred to as Greater Whitehall, this additional annex made the Whitehall Building New York City’s largest office building in its time.
In 2018, the decaying original sculptural limestone and terra cotta comprising the pediment at the top of the original building and annex were completely removed as the beginning of a large-scale restoration of both the original building and the Greater Whitehall annex. Due to the natural decay and eventual removal in 2018, much of the original limestone and terra cotta ornamentation was lost. Leaving behind nothing but historic photography, a few elevations, and a handful of intact ornamental elements. Further into the restoration process, experts were brought in to address the missing ornamental terra cotta and limestone.
A mixture of rigid Forton molds and rubber molds were created onsite of the few elements that were in fair enough condition, however many required sculpting or some form of repair to fill in the missing details caused by water damage and other forms of natural decay. The rest of the missing ornamentation had to be individually hand-sculpted in-studio, solely based on historic photographs and site dimensions. The restoration of the Greater Whitehall annex’s pediment ornamentation alone totaled over 300 individual pieces and 500 square feet of GFRC Replacement ornamentation.
Technique Highlight
Sculpting and Mold Making at Full Scale
Over the course of a building’s or structure’s natural lifespan, it will encounter a never ceasing source of stress, erosion, and decay simply from natural weather cycles. Affecting everything from the structure of a building to the smallest details of its ornamentation. Years of wind and rain, alongside temperature fluctuations brought on by the changing seasons and even heat from the sun; will inevitably cause erosion and create fractures between the ornamentation and the structure, and create fractures within the ornamentation itself. This inexorable process struck the Whitehall Building, and in 2018 all of the ornamental limestone comprising the pediment of the Greater Whitehall Annex was removed out of safety and marking the beginning of a long restoration process of both the original structure (built in 1904) and the larger annex (built in 1910). A side effect of the pediment ornamentation’s removal was its unfortunate destruction caused by the internal stress fractures of natural weathering.
When original, highly sculptural architectural ornamentation is being replicated, the best case scenario is that there are some original intact pieces. Wherein the beginning of the restoration process consists of either taking a 3D digital scan (a much more modern practice), or various different types of molds are utilized. Moldmaking is still oftentimes the preferred method, as scanning still does not capture all of the intricate details accurately. Broadly speaking, molds are made in two ways: with a gypsum mold, or a rubber and mother mold. Gypsum molds are generally quicker, lighter weight, and more cost-effective, but because of their rigidity, they can’t capture deep details with heavy undercuts (places where a detail is so dimensional that a rigid mold would get locked into place and be impossible to demold). If a rigid mold was made of a hand or foot, the only way to demold it would be to cut the rigid mold around the entirety of the form’s details. A rubber mold, on the other hand, can flex around deep details and undercuts. So a mold of the same form may require a slit around one side, but one might be able to essentially pull the rubber off like a glove. These molds capturing the detailing of a facade are made and taken back to a studio to assist in the recreation of its ornamentation.
The recreation of the pediment’s sculptural portions began with large blocks of EPS foam to fill the volume of the sculpt. The foam blocks were hand-carved and rasped to establish a rough armature. This armature was then coated with molding plaster, and tooled in place to capture the fine details. Once work on the sculpting was completed, it was sanded and polished smooth. At every step of the process, the piece was checked to ensure dimensional compatibility with the existing ornament. Of the few existing details; plaster casts were made from the site molds, and missing details were sculpted in. Afterwards, the finished pieces were prepped for mold-making. These final molds were then used to cast the replacement GFRC ornamentation. This delicate casting process requires thorough knowledge of the coloring and eventual aging of natural limestone to ensure a clean continuous look. Now from street, and even roof level, the sculptural pediment shows a seamless newly restored facade of the Whitehall Building, and is once again a stunning example of Renaissance Revival architecture.
The most difficult scenario is when there is no original ornamentation, and pieces must be sculpted from scratch. The Pediment ornamentation of the Greater Whitehall annex was an unfortunate hybrid scenario - where much of the original ornamentation was lost and destroyed in the beginning of its restoration. Of the few existing original details remaining, a mixture of rigid Forton molds (of the simple patterning and general forms), and rubber molds (of primarily the organic fauna ornamentation) were made.
The vast majority of limestone ornamentation, consisting of the shields, adjacent corbels, and modillions were completely missing leaving behind only historic photos and site dimensions for reference. Creating an incredibly difficult situation in the overall restoration as extreme precision was needed to ensure there would be a perfect and continuous fit into the existing original limestone, therefore the entire project was also sculpted at full-scale from start to finish. Further exasperated by the shear amount of missing ornamentation comprised of 300 individual pieces or 500 square feet of sculptural limestone.
