899 S. Plymouth was designed in 1979 by Ezra Gordon, Jack M. Levin and Associates Architects. The building is divided between a high-rise residential tower and low-rise commercial space. The high-rise has a footprint of approximately 130 feet by 73 feet reaching 26 stories tall plus a penthouse. The low-rise footprint is approximately 83 feet by 73 feet and is two stories high. The low-rise portion has commercial spaces on the first floor with a sun deck and a pool deck at the roof. Both decks consisted of a concrete topping slab over a buried membrane on top of a concrete structural slab. Multiple leaks were reported in the low-rise portion of the building.

After completing a condition assessment of the sun deck and pool decks, which included opening inspections at the concrete topping, Klein & Hoffman made the recommendation to replace the membrane. The membrane was original to the building and was beyond its serviceable life.

There were several challenges with this project including a shortened time-frame. We developed a schedule to keep the pool open as long as possible during the summer and have the pool deck ready for use the following spring. The last challenge of the project was the height from the structural slab to the top of the walking surface which limited the insulation and flashings that could be installed. The first step was to provide a waterproof coating (polyurethane waterproofing, traffic bearing membrane) at the pool equipment room located under the pool. The coating would provide additional protection to the first floor commercial spaces while the roofing membrane was being replaced. The concrete topping slab and roofing membrane were then removed and a temporary roofing membrane was installed. After repairing sections of the structural slab and adding roof drains, hot fluid-applied rubberized asphalt roofing membrane, insulation and plaza-deck pavers were installed. PMMA flashing was provided around the perimeter of the pool. Electric Field Vector Mapping (EFVM) testing was completed prior to the installation of the ballast to confirm the integrity of the waterproofing membrane.