Unlike other systems that rely on fasteners, adhesives or ballast, a wind-vented roof system is a roofing system that takes advantage of negative pressure or the wind to help secure the roof. The harder the wind blows across your roof, the tighter it holds down. Wind vented roof systems are gaining popularity with contractors; there is no history of failures among companies with more than 15 years of experience using the technology.
The science behind the system is simple. When an air seal is created using a newly installed single-ply membrane, a low pressure condition is created on the underside of the roof. Any moisture in the existing wet roof insulation is pulled up through perimeter roof vents.
Benefits of the wind-vented system include the re-use of existing insulation instead of removal and disposal which results in significant cost savings; restoration of insulation value to the roof, with the option to increase R-values; easy application that can be done on a strict deadline; and easier maintenance compared with ballasted roof systems.
The system usually does not require a tear-off of the existing roof and work proceeds faster and with less intrusion on building occupants. And, from a sustainability point of view, there is little or no roofing waste going into a landfill. The labor and materials savings when avoiding a tear-off are also significant.
All of these benefits add up to a recover system that is less expensive than adhered roofs where insulation has to be removed.
The roof system is also beneficial if you are working within a tight deadline, which is common with schools and universities looking to reroof during a winter or spring break.
While most recover systems require a cover board, the wind-vented design allows contractors to install directly over existing adhered single-ply membranes if the insulation below is secure. Roof fasteners are often not required with the wind-vented system, while traditional roofing options require a tear-off down to the non-nailable deck. Hot mopping, cold adhesives or low-rise foam are then necessary to adhere the insulation or new membrane. When installing the wind-vented roof system, the design burden on the contractor is light. The number and layout of the roof vents is determined by building height, parapet walls and a variety of other factors determined by the system manufacturer. On average, about 12 vents are needed for a 150-square roof. The process is streamlined and fast.
In addition to the simple installation, the 0% failure rate, and sustainable nature of the wind-vented roof, it has been tested and proven effective in severe hurricane and strong winds.