Blow-In Insulation on Sloped Ceiling?

TheGrinch

I'm at the insulation phase with my house and there are two rooms with vaulted ceilings (but flat top), around a 4/12 slope (30 degrees). Do you have to use bat insulation on those or will the blow-in insulation stay there. I'm sure you'd have to build it up at the base a little bit but I've never used blow-in.

The largest room is about 16'x16', so the side of the ceiling that's slanted is about 7 feet with about a 4' wide flat section at the top. Please help the dummy. Thanks!

Scuba_Dave

Are the ceilings vented - soffit & ridge?

TheGrinch

Soffit (vinyl) vented every third. Ridge top vents span all of the ridges of the house.

When I say "vaulted". It's not like a real vaulted ceiling. The real roof is several feet above the ceiling.