On Thu, 14 Jun 2007 21:08:07 -0000, handsome greg
wrote:

I've got a portion of a roof built with 2x4 rafters. I'm trying to
stuff R30 in the space with some airspace-savers underneath, which
would normally warrant 2x10's instead. What would be the best way to
build these 2x4's out to the depth I need for my insulation? Running
2x10's next to the 2x4's would be annoying, but is the only answer I
can come up with. Any suggestions? Any possibility of getting away
with 2x6's attached to the face of the 2x4's? Thanks for the advice!

You only put insulation in between the ceiling joists, NOT the
rafters.