Low-rise polyurethane foam insulation adhesives have become increasingly popular since their introduction into the roofing industry about 30 years ago. They can perform well and offer a number of advantages over mechanical roofing fasteners.
Designers may prefer low-rise foam adhesives to other securement types for certain applicationsfor example, with new roof system construction and reroofing over non-nailable decks, such as pre-cast or poured-in-place concrete; where mechanical fasteners may compromise a roof deck's structural strength, such as reroofing applications over cementitious wood fiber decks; where job-site restrictions rule out the use of asphalt adhesives; or where a design objective is to avoid penetrations or thermal bridging associated with metal fasteners.
Also, when designing for extreme wind loads, low-rise foam adhesives can provide wind uplift-resistance levels not available with other adhesives or impractical with mechanical fasteners.
On the other hand, low-rise foam adhesives present many more opportunities for performance problems than other roof system attachment methods mainly because low-rise foam adhesives are sensitive to job-site and environmental conditions and unforgiving of deviation from manufacturers' application recommendations. Your understanding of the considerations associated with low-rise foam adhesives can be critical to roof system performance.