Attic Ventilation
It is recommended attics be vented one (1) square foot of free vent area for every one hundred and fifty (150) square feet of ceiling area. Proper ventilation will help to keep the house cooler during warm weather and extend the life of roofing materials.
All diagrams are from Code Check ® - Building, by Michael Casey, The Taunton Press, 2003. Code Check itself is based upon the International Residential Code (IRC) for 2003.