Taking its name from a hidden rooftop addition that contains a three-story penthouse, The Stealth House by New York-based WORKac is unassuming when viewed from the street, through dramatically-modified, modern residential spaces dwell behind the facade. Due to strict city requirements, any rooftop addition to the historic structure was to be invisible. This called for a strategic analysis of the site and corresponding cones of view, resulting in the sculptural, angular form of the addition.

The 1857 facade was completely restored with a new charcoal color that references the building's history. In collaboration with artist Michael Hansmeyer, new versions of the original Corinthian column capitals were created through 3D modeling.

On the interior, the designers combined new concepts of urban living with nature-inspired elements. Murals of trees created from mosaic tiles line the bathroom walls. Each of the single-floor units has built-in composting, an herb garden in a four-foot tall "bonsai" space above the kitchen, and a fern landscape connected to the master bathroom, watered by steam from the shower condensing on the glass enclosure.

The penthouse combines sleeping spaces and a family room within the original fifth floor of the building. Entertaining and dining areas fill the space under the new angular roof perched atop the highest floor. Outdoor spaces are hidden behind the original pediment, while a hot tub fills a repurposed elevator bulkhead.

At a distance, the design appears simple, but upon closer view, the elements of modern intervention and new contemporary design come to focus.