This is a half roof with the eave vents at the top and bottom eaves.
It covers a large second floor room, with a loft space near its upper
edge. We sleep up there.One would have to be careful not to overfill
the space, and to leave room at both eave vent ends as well so as not
to block the circulation.

By "half roof", are you referring to the sloped portion of the ceiling
above a knee wall, like the portion to the right of the knee wall in
this illustration?

http://oee.nrcan.gc.ca/residential/p.../knee-wall.gif

Michael Thomas
Paragon Home Inspection, LLC
Chicago, IL
mdtATparagoninspectsDOTcom
847-475-5668