I can see where (starting at the point where the knee wall meets the
angled ceiling wall) the angled ceiling sheetrock is supported by the
same series of 2x4 (2 x 6?) that are used for the roof support. In
other words, there is
roofing
plywood (on top of supporting stud)
roof supporting studs --with insulation between the studs (no air
space)
sheetrock (on bottom of supporting stud)

Thanks.