In 1987, Rockrose commissioned Avinash K. Malholtra to design a new 8-story apartment building to be combined with an adjacent existing, red-brick, 6-story apartment that had been erected in 1900.

The attractive project is known as 110-114 Horatio Street and contains 159 rental apartments.

The new building, which is also known as 509 West Street, has a orange and tan brick façade with discrete air-conditioners and a canopied entrance with globular wall scones and inset pilasters. It also has a pitched central portion of its roofline and a very attractive pergola designed by Howard Zimmerman Architects on its roofdeck. It has no sidewalk landscaping.

The two buildings share a courtyard that is unusual for its landscaped "mountain" and the courtyard permits light to reach the public corridors on each floor. The older building, which was originally the Devoe paint factory building and is an official city landmark, has high ceilings. The new building, which overlooks the Hudson River, has a revolving front door.

In August, 2009, the Elghanayan brothers who owned Rockrose split up with the elder brother, Houchang (Henry) Elganayan, keeping the Rockrose name and retaining control of this building and 200 Water Street, the Archive bnilding, 100 Jane Street and Midwest Court on 53rd Street, and 22 River Terrace and Tribeca Point in Battery Park City and Plaza East in Kips Bay and the East Coast in Long Island City. The younger brothers, Thomas and Frederick Elghanayan, formed TF Cornerstone and retained 99 John Deco Lofts, 2 Gold Street and 455 West 47th Street. The Real Deal said that they might be also retain 45 Wall Street, Chelsea Centro on 26th Street, Turtle Bay Towers on 46th Street, the Fairfax at 201 east 69th Street and the West Coast at 95-97 Horatio Street.