Award of Excellence: Special Projects Category
Roof Sundeck Rehabilitation at Chicago Condominium Complex
Submitted by CTLGroup
Carlyl Apartments Homeowners Association
National Restoration Systems, Inc.
Rolling Meadows, IL
Rediger Associates, Inc.
St. Charles, IL
American Hydrotech, Inc.
The roof sundecks, constructed circa 1966, are located at the north and south ends of a 39-story luxury condominium building. Typical plan dimensions of each sundeck are approximately 71 by 40 ft (21.6 by 12.2 m). Structural framing consists of flat-plate floor slabs supported by concrete columns.
By 2005, the sundecks were besieged with problems associated with persistent widespread water infiltration into the interior, concrete slab deterioration, decaying wood decking, and severe corrosion of the original railings and outrigger rope descent systems.
The building owner engaged consulting engineers to perform a comprehensive field investigation and materials test to determine the extent of deterioration of roofing, concrete slab, steel railing, and rope descent systems; evaluate the causes of leakage; and recommend appropriate steps for repair and maintenance. The results led engineers to recommend complete replacement of the roofing, decking, railing, and rope descent systems. A life-cycle cost analysis also indicated that complete replacement of these sundeck elements would provide better value over time compared to a partial replacement/patch repair scheme. Due to the localized nature of roof slab deterioration, concrete patch repairs were recommended. Based on a detailed structural analysis, structural strengthening of several supporting concrete columns was necessary to accommodate code-prescribed design loads.
This work required extreme care in design, sequencing, and execution to access sundecks on the building roof via swing stages, maintain structural support during column strengthening repairs, and minimize disruption to the regular use of the building. Even so, the base bid work on this project was completed ahead of schedule and under budget. The durability and aesthetics of the sundecks are improved significantly.