The ventilation amount and opening size requirements can be found in section 806 roof ventilation of chapter 8 roof ceiling construction.
Roof ventilation irc 2015.
Vented attics shall have a minimum net free ventilation area at least 1 300 of the area of the vented space.
Ventilation openings shall have a least dimension of 1 16 inch 1 6 mm minimum and 1 4 inch 6 4 mm maximum.
Chapter 9 roof assemblies chapter 10 chimneys and fireplaces.
R806 roof ventilation r807 attic access.
Enclosed attics and enclosed rafter spaces formed where ceilings are applied directly to the underside of roof rafters shall have cross ventilation for each separate space by ventilating openings protected against the entrance of rain or snow.
The international code council icc is a non profit organization dedicated to developing model codes and standards used in the design build and compliance process.
R806 5 unvented attic and unvented enclosed rafter assemblies.
The international codes i codes are the widely accepted comprehensive set of model codes used in the us and abroad to help ensure the engineering of safe sustainable affordable and resilient structures.
Between half and two thirds of the provided ventilation shall be installed at the eaves.
International residential code 2015 irc 2015 part i administrative chapter 1 scope and administration part ii definitions chapter 2 definitions part iii building planning and construction.
The ventilation openings shall have a least dimension of 1 16 inch 1 6 mm minimum and 1 4 inch 6 4 mm maximum.
This shortcut conveniently calculates the 2015 international residential building code minimum irc section r806 roof ventilation 1 which states in part 1 square foot of net free area for every 150 square feet of attic floor space with the attic defined as length x width floor of the attic.
2015 international residential code for attic ventilation air vent inc.
The majority of the requirements related to attic ventilation have not changed much from the previous editions.