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2021 International Residential Code for One- and Two-Family Dwellings

Every 3 years the International Residential building Code (IRC) releases code updates. 2021 is a cycle year. Below is the attic ventilation section. Key notes:

 

  • The minimum amount of attic ventilation remains 1/150 (1 square foot of Net Free Area for every 150 square feet of attic floor space. Attic floor is defined as length x width FLOOR of the attic).

  • The amount of ventilation can be reduced to 1/300 (in effect 50% less) BUT 2 conditions must be met (read the full code language in the PDF below).

  • Renewed for 2021 is the requirement that “Vents must be installed according to the vent manufacturer.” This includes: Don’t Mix Exhaust Types (ridge vents, wind turbines, box vents, gable louvers, power fans); and Exhaust Ventilation Must be Balanced with Intake Ventilation. (see the Installation Instructions for the ventilation product).

 

 pdf smallRead the full 2021 Bulletin Here

 

 

Air Vent Contractor LocatorOur exclusive Contractor Locator will allow you to find contractors in your area who can assist with Air Vent product installation—including solar attic fans and skylight tubes. Click the link below to register and get started.

 

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