Ventilated Roof System Calculator

Proper roof ventilation is critical to the longevity and effectiveness of the roof system. Commercial buildings are larger with longer runs, a larger surface area of the roof, lower pitches and larger heating and cooling systems. All of these characteristics influence the ventilation of the roof and should impact proper product selection. However, there has been a distinct lack of definitive data within the industry explaining the interaction of these variables making product recommendations difficult.

Metal-Era sponsored an independent, third-party study to determine how the below variables interact and impact commercial ventilation. This calculator will assist you in determining the ideal airspace relative to your project's ventilation needs. To calculate the net free area for an attic ventilated roof system, check out our NFA Calculator.

Instructions The default values listed provide an example of typical summertime conditions in an inadequately ventilated system. Input the the values from your next project to determine if you have the proper airflow. Your project will be graphed and will illustrate the effectiveness of the proposed system.

Roof Shape Details Pitch on 12: Length of passage from eaves vent to ridge vent:  feet Thickness of OSB/Plywood:  inches Height of Air Gap:  inches Ridge Length:  feet Eave Length:  feet

Thermal Information Roofing Composition: Full Sun  Snow Covered Roofing Material: Cement - Dark Cement - Medium Cement - Light Ceramic - Red Ceramic - White Shingle - Dark Shingle - Medium Shingle - Light Wood - Dark Wood - Medium Ceiling/Wall Insulation R-Value: Outside Temperature:  °F