Flap Exhaust Valves (Flap Stacks)

Regular price $535.10

A resourceful after-the-fan product, flap exhaust valves, or stacks, are designed to open, like bird wings, with the airflow and close when the system is not exhausting. The lightweight and balanced blades produce minimal resistance to exhaust. The design of the housing and blades channel rainwater away from the opening and allow it to drain without intrusion into the ducting. 

  • Available in 4" to 32" diameter (contact for custom sizes).
  • Also known as winged stack.
  • Products come with raw ends. Diameters are +/- 1/8 inch.
  • Alternative Solutions: No-Loss Stack, Jet Cap, Rain Cap