The majority of the requirements related to attic ventilation have not changed much from the previous editions.
Roof venitlation in irc 2015.
The following are the requirements taken directly from the irc.
For vented and unvented i e.
Pa302 1 ceilings with attic spaces n1102 2 1 r402 2 1.
The 2015 irc requires r 49 insulation for ceilings with attic spaces.
Please refer to the ventilation manufacturer for product installation and limitations.
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.
Conditioned attic spaces the 2015 irc section r806 and ibc section 1203 have specific requirements.
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.
The ventilation amount and opening size requirements can be found in section 806 roof ventilation of chapter 8 roof ceiling construction.
Unvented attics and unvented enclosed roof framing assemblies created by ceilings that are applied directly to the underside of the roof framing members and structural roof sheathing applied directly to the top of the roof framing members rafters shall be permitted where all the following conditions are met.
Chapter 9 roof assemblies chapter 10 chimneys and fireplaces.
R 38 shall be deemed to satisfy the requirement for r 49 wherever the full height of uncompressed r 38 insulation extends over the wall top plate at the eaves.
R806 5 unvented attic and unvented enclosed rafter assemblies.
R806 roof ventilation r807 attic access.
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.
Section r806 roof ventilation r806 1 ventilation required 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.
Air vent provides a complete line of ventilation products that meet the highest standards for quality and performance.
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.
Building code plus a building envelope specialist should be consulted in the design and specification of attic ventilation.
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.
