What is the "vented airspace"?


The "vented airspace" refers to spaces which have the ability to move air from the space that will be vented to the outside. This is a common practice in attics where the building codes require that the space be "vented" and they specify the amount of air movement by a percentage of the ceiling area (1/150 or 1/300 depending on the vapor barrier). 

For more information, see WCD #6 - Design of Wood Frame Structures for Permanence.Download free here.