The limestone façade restoration and modern renovation of this townhouse involves all of the complex issues encountered in an extensive building renovation. The interior core was reframed to create a breath-taking 6 story atrium and custom curved stair gallery capped of with an oval skylight. A rear three story extension houses a second stairway to the roof terraces and the new copper penthouse. To accommodate a forty foot lap pool, a 20 x 50 foot crawl space in the basement was excavated down 15 feet, while underpinning the existing 5 story masonry bearing walls above. In addition, a 12 foot vault space was excavated underneath the entire front sidewalk to create a wine cellar. Working within the demanding constraints of a narrow lot, the mechanical, plumbing, lighting, and electrical systems were precisely designed to achieve clean and fluid spaces. Approval was required by the New York City Landmarks Preservation Commision.