Case Study: Helmsley Building achieves historic façade restoration and preserved terra cotta with Thornton Tomasetti

Helmsley Building restores 74 bison heads with Thornton Tomasetti

The Helmsley Building, a historic New York City skyscraper, required a comprehensive facade restoration to address severe deterioration of its iconic terra-cotta elements, including massive columns and bison heads, and the corrosion of embedded structural steel. Thornton Tomasetti was engaged to provide structural engineering and restoration expertise to tackle these complex preservation challenges.

Thornton Tomasetti implemented innovative solutions including finite element modeling to diagnose stress cracks, specialized anchors for stabilization, and an impressed current cathodic protection system to halt steel corrosion. They salvaged and repaired most of the original terra cotta and used advanced fabrication methods for new pieces. This approach preserved the historic fabric, provided significant long-term cost savings over full replacement, and set a new precedent for the safe and economical repair of historic terra cotta.

Helmsley Building