Midtown South-based Mortar Architecture + Development has filed applications for a five-story, 10-unit residential building at 91 Diamond Street, in Greenpoint. The project will measure 14,431 square feet and rise 50 feet to it roof. The residential units should average 999 square feet apiece, indicative of condominiums. There will be bicycle storage in the cellar. Mortar will is also listed as the architect of record and will design the project in-house. The 5,000-square-foot plot is vacant.