Work continues to unfold on Manhattan’s largest outdoor roof deck at 341 Ninth Avenue, a ten-story office building in West Chelsea. Tishman Speyer is working with the United States Post Office to redevelop the 2.2 million-square-foot Art Deco-style structure, known as the Morgan North Postal Facility, converting the upper floors into 650,000 square feet of modern office space with a 2.5-acre green roof. The property will also yield 5,000 square feet of ground-floor retail space facing Ninth Avenue. CBRE represented USPS in prior negotiations with Tishman Speyer for the Midtown, Manhattan project, which occupies the full block from Ninth to Tenth Avenues and West 29th to West 30th Streets. Urban Atelier Group is the general contractor for the project.