Fig. 1 – High Line 519 from W23rd Street.

High Line 519 is the first new residential building completed under New York City’s 2005 West Chelsea rezoning plan that greenlit the transformation of the abandoned elevated rail line on the westside of Manhattan into a park. It is an eleven-story residential condominium on a 25 ft-wide slither lot on W23rd Street.


Fig. 2 – Looking north from W17th Street shortly after the high line was built.

Fig. 3 – Looking east along 30th Street in the 1950s. Photo credit: Jim Shaughnessy.

Fig. 4 – High Line on Manhattan’s westside extends from Gansevoort Street to Hudson Yards.

Fig. 5 – Pressure to demolish by real estate interests was overcome, and the railroad right-of-way was preserved for future use.

Fig. 6 – High Line trestle model.

Fig. 7 – Aerial view looking towards W23rd Street.

The defunct railroad trestle that undergirds High Line Park effectively lifts the city sidewalk up two stories, bringing a highly choreographed public thoroughfare into alignment with the third floor of adjacent buildings. The direct interface between public street and private residence typically limited to the first building floor, is now stretched to encompass several lower floors, prompting a rethinking of the W23rd Street building façade.

Fig. 8 – Sequestered New Yorkers lean out of windows to applaud emergency workers during the Covid-19 lockdown in 2020. Photo credit: Angus Mordant, Daily News.

Fig. 9 – High Line 519 fourth floor apartment seen from W23rd Street.

To leverage the High Line’s new public zone we asked: Could value-adding openings to the outside give each floor-through apartment a distinctive visual address while creating a collective identity for the building as a whole?

Fig. 10 – High Line 519 third floor apartment resident looks out towards the High Line.

Fig. 11 – Typical floor-through apartment plan.

The building volume prescribed by the zoning envelope for the 25 ft wide slither lot presented a challenge. Its tall, narrow proportion required a disproportionate percentage of the construction budget to address lateral stability of an eleven story building, and given the relatively small floor plates, design had to be strategic.

Fig. 12 – Connection between the fifth floor apartment and the High Line.

Balconies are not permitted to overhang W23rd Street, but New York City regulations allow ‘decorative architectural features’ to project several inches over the street-facing lot line. To avoid encroaching on sellable interior space and the likelihood of losing design features to inevitable value engineering, 4-inches of ‘free space’ was used to create an identity for the building.

Fig. 13 – A silhouette of the balustrade pattern is visible from ‘the 23rd Street Lawn’ looking west. Photo credit: Iwan Baan.

Fig. 14 – South façade balustrade pattern studies.

Fig. 15 – Optical effect of hexagon-embossed perforated stainless steel sheeting.

Fig. 16 – Family of balustrade shapes.

A series of perforated stainless steel balustrades skim the W23rd Street façade, linking staggered French doors of each successive apartment. Balustrades are fabricated from hexagonally embossed perforated stainless steel sheets, an economical industrial material typically used to line the drums of washing machines. Optical effects where explored both at the scale of the exterior façade as a whole (refs. 2 and 3), and at the scale of a perforated surface (ref. 4).

Fig. 17 – W23rd Street view with Neil Denari’s neighboring High Line 23 employing a resonant geometry.

Fig. 18 – South and north façades.

Fig. 19 – Balconies on the north in a snow storm.

Fig. 20 – Looking south from the High Line.

Fig. 22 – From the High Line at W23rd Street.

Fig. 21 – W23rd Street façade.

Fig. 23 – Looking east along W23rd Street.


New York, USA




18,600 sqf


Residential condominium

systems and materials:

Steel, concrete, glass, stainless steel, composite wood panels


Sleepy Hudson

project team:

Lindy Roy with Jason Lee, Joon Ho Kim, Erhard An-He Kinzelbach, Adam Rouse, Heidi Werner

Related Projects:

Cairnhill Circle Towers, Tahama Street Tower

selected publications:

John Hill, Guide to Contemporary New York City Architecture (New York: W.W. Norton and Company)

Sara Mercer, “ROY completes High Line 519” World Architecture News, (January 8, 2008)

Robert A. M. Stern, David Fishman, Jacob Tilove eds., New York 2020 (New York: Monacelli Press)

Peggy Tully ed., Modern American Housing: High-Rise, Reuse, Infill  (New York: Princeton Architectural Press)



Ref. 1 - Hubel and Wiesel (1962) sequence of visual processing in the striate cortex.

Ref. 2 - No physical demarcation between foreground and background, yet a white square appears in the center of the image.

Ref. 3 - Horizontal lines appear skewed but are actually parallel.

Ref. 4 - Akiyoshi Kitaoka et al, "The Eye Pupil Adjusts to Illusory Expanding Holes", Frontiers in Human Neuroscience Volume 16 - 2022.