Volume 8, Issue 9 (October 2011)
Case Studies of Foamed Adhesive Failures of Low Sloped Roofing Rigid Insulation Board
In low sloped roofing systems, poorly adhered roofing assemblies are unable to resist significant wind loads and are likely to be further damaged or destroyed by wind events well below the design wind pressures for the assembly. The design and installation of rigid insulation boards are a critical parameter in the service life of this roofing assembly in that, if the insulation boards become detached, there is increased risk for complete roofing assembly failure. Foamed adhesive is a common alternative to traditional hot-mopped asphalt adhesive in contemporary roofing assemblies. The proper design and installation of insulation board roofing assemblies in foamed adhesive is paramount to the successful performance of these roofing assemblies. Some of the critical parameters that could influence foamed adhesive performance are: insulation board adhesive pattern defects; insulation board adhesive quantity; inadequate insulation board adhesive contact; and failure to maintain insulation board contact with the substrate until the insulation adhesive is sufficiently set. The present paper discusses these critical parameters through case studies that clearly demonstrate how these parameters can lead to the failure of roofing assemblies, and discusses the lessons to be learned from these insulation board adhesion failures.