Phase one of Mercer Street involved developing three designs to persuade the Preservation and Landmarks Commission that a three story residential addition to an existing building could be appropriate within the SoHo Cast Iron Historic District. The three schemes continued the proportions and datum lines of the adjacent cast iron buildings. The first had a facade of vault lights, used throughout SoHo to bring light to manufacturing spaces below sidewalks. The second scheme added much-needed green space to the neighborhood by a cast hydroponic screen. The third design respected that the addition was above a masonry building by placing a glass brick facade at the face of the building. While the designs were praised for their neighborhood appropriateness, the Commission decided that the building's birth-date of 1863 - preceding the cast iron buildings- lent enough historical significance so as to prevent any visible addition.