Preventing Failures in Hot-Applied Rubberized Asphalt Systems

October 30, 2011
Publication: Proceedings from the RCI Building Envelope Technology Symposium 2011

Abstract: Hot fluid-applied rubberized-asphalt waterproofing membranes have a long track record of performance.  As designers strive to incorporate occupant-accessible rooftop plazas and vegetative roofs into their projects, these membranes have become a popular choice for waterproofing systems. However, recently, the roofing industry has observed a number of issues with the application of hot fluid-applied rubberized-asphalt membranes, including widespread delamination, pinholing, and blistering. In the past, these issues were primarily attributed to moisture in the concrete slab. Using quantitative tools to measure moisture content in concrete slabs, it has been determined that some failures can also be attributed to factors such as primer application, material application, membrane temperature, and others. The presenter has found that successful application is highly dependent on a combination of issues, such as the age and moisture content of the concrete substrate, proper primer application and dryingtime, well-timed application of the membrane, and a project-by-project series of adhesion tests.  With reference to project-based experiences, this presenter will discuss failure modes in fluid-applied rubberized-asphalt membranes and present successful solutions, including modifications during the design phase, in-field mock-up testing, and other quality control measures.