Located throughout the city of Milwaukee, Wisconsin, and neighboring towns, the Milwaukee Public School System (MPS) buildings’ roofs were in bad shape after years of wear and tear. The buildings were under threat of closure due to unsafe conditions. New roofing and drainage systems were implemented to solve safety concerns and extend the life of the historic school buildings.
The school system simply added new material on top of the previously damaged roof. The short-term fix created a myriad of issues, including pooling and drainage problems. It also made the roofs very heavy.
MPS and a roofing manufacturer team began by conducting a visual inspection, where each roof was checked for obvious cracks, holes, or punctures. From there, the team evaluated for moisture using infrared technology, and conducted test cuts to further examine any potential damage under the surface. They were then able to cut out any moisture damage found and replace as necessary.
The team designed and installed a roofing solution that would prevent rainwater ponding, was lightweight, had low heat transfer, and was built to last. Utilizing a roofing system that creates positive drainage would ensure the rainwater would not pool on the roof, thereby reducing damage and the number of new leaks.
The teams worked together to create a system featuring a tapered polyisocyanurate (ISO) insulation system using a certified drainage program (CDP).
CDP is a comprehensive low-slope tapered design service to eliminate ponding water on a roof’s surface. The program’s designs help to prevent structural roof collapse, moisture invasion, membrane degradation, loss of thermal resistance, ice formation, vegetation growth, and voiding system warranty.
The first step in the CDP process was to conduct a full auto-level survey to measure for irregularities in slope causing drainage issues. In order for a roof to drain properly, a positive slope of about 3 mm (1/8 in.) was required. Once the survey was complete, the roofing specialists created a grid based on the auto-level transit.
Before implementing the CDP system, each school was only getting 20, 15, or as few as 10 years out of a roofing surface. Now the MPS team expects their roofs to last at least 30 years.