Type: Restoration - Plaza
Project Name: United Nations
City: New York
State: New York
Client: United Nations

Features: Structurally supported portion of plaza and North Building. Concrete slabs over steel beams supporting landscape.

Description: DESMAN Associates performed comprehensive inspection and condition assessment of the Plaza and the North Building Conference Balcony, in order to identify the causes and sources of the water infiltration, degree of structural deterioration and remedial repairs. DESMAN?s services included, assessment of the steel beams and beam pockets supporting the concrete slab under the landscaped area and waterproofing evaluation of the structurally supported plaza. In addition, DESMAN also conducted structural investigation and waterproofing evaluation of the North Building Conference Balcony. This balcony overlooks the plaza grounds, gardens, and the Hudson River. The balcony opens to the main assembly hall and the UN building, and serves as a congregation area for the UN delegates. The Balcony structure consists of concrete paving slabs, rigid insulation with protection board, gravel, five-ply built up membrane with protection board and concrete fill, all supported by a concrete structural slab with metal decking on structural steel framing. Two stage drains were designed and installed to remove the water from the surface runoff, as well as from the built up portions of the balcony?s topping slab. The Balcony has been experiencing water infiltration into the office spaces below. Based on the investigation results, several repair alternatives along with associated costs, life cycle, waterproofing, alternative pavers, and maintenance issues, etc., were suggested to the UN for the repairs and replacements. DESMAN is currently in the process of preparing design repairs and specifications based on the UN?s preferred budgets and programs. DESMAN will also provide technical support and construction administration during repairs.