Dura-Ply’s Vapor Venting Roof
The DRI Roof™
An innovative vapor transport system that will enhance resiliency in all climates.
The negative air pressure exerted on a roof system is similar to inflating a balloon; as the pressure increases inside of the balloon, the pressure (force) exerted on the skin of the balloon increases. The main difference between a balloon and a roof system is that your roof system experiences positive uplift force because wind passing across your roof creates a suction effect which exerts force on the roof system. This force wants to pull the roof system away from the roof structure.
Assuming that your roof structure has been engineered properly, the wind uplift force could cause the roof system to fail (if the roof system anchoring is insufficient) while leaving the roof structure unharmed. In a worst case scenario, an inadequate roof system anchored to an inadequate roof structure can lead to a complete roof failure.
A good example of how wind uplift force affects a roof system can be shown through the comparison to two different EPDM membrane roof systems. One that is NOT vented, and the Dura-Ply System. It starts with a mechanically fastened EPDM membrane. This system utilizes a reinforced membrane and is attached directly to the decking using mechanical fasteners and plates in the laps. The insulation is also attached to the decking using specially designed mechanical fasteners and plates.
There are then, specially designed Dura-Ply vents placed stategically on the roof, along with a membrane and “tunnels” that dissapate the air and air pressure through one-way vents. With the Dura-Ply System, the wind uplift force is exerted directly on the membrane. This means that the negative air pressure is trying to pull the membrane away from the decking. This force is transferred directly to the membrane fasteners and through the tunnels and vents to eliminate the suction force that can cause roof failure.