Attic ventilation can be a confusing, complex subject and is the topic of many discussions, research papers and articles. For example, in the June 2012 issue, the article "Vexing ventilation issues" focuses on building code requirements for attic ventilation. In the article, there was some discussion about unvented attic assemblies because the 2009 International Residential Code® (IRC) introduced provisions allowing this construction type. Some readers found the concept of unvented attics even more confusing than attic ventilation. And NRCA has received numerous calls from homeowners and contractors regarding converting existing attics into unvented attics.
Ventilating attic spaces is viewed by many roofing professionals as a technical requirement for steep-slope roof assemblies and often is a building code requirement. However, as mentioned, attics can be designed to be vented or unvented.