2006 Irc Roof Ventilation

Name of legally binding document.

2006 irc roof ventilation.

This picture shows the typical attic ventilation requirements as well as how ridge vents work. Also when using a vapor retarder in an attic space irc 2012 limits the net free ventilation reduction from 1 150 to 1 300 for buildings in climate zones 6 7 and 8. Ventilation openings shall have a least dimension of 1 16 inch 1 6 mm minimum and 1 4 inch 6 4 mm maximum. International residential code name of standards organization.

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. Openings in roof framing members shall conform to the requirements of section r802 7. Nrca guidelines regarding attic ventilation nrca recommends designers provide at least 1 square foot of nfva for every 150 square feet of attic space 1 150 ventilation ratio. R806 2 minimum vent area.

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. Excessive moisture can allow microbial growth and rust metal parts. The amount of attic cavity ventilation is specified by numerous ratios of free vent area to insulated ceiling area ranging from 1 150 to 1 600 depending on which building code is consulted the 1 300 ratio being the most common. Required ventilation openings shall open directly to the outside air.

See irc section 806 for more details. Main reasons for attic ventilation to prevent excessive moisture buildup on building components. Addeddate 2012 07 31 18 53 03 identifier gov law icc irc 2006 identifier ark ark 13960 t30301r3c ocr abbyy finereader 8 0 ppi 300. Ducts in crawlspace must be sealed and have r 8 insulation.

Click image to enlarge.