jimbob,

As I am in the process of remodeling my second room from total teardown
and well on my way to journeyman carpenter in the process.. LOL The
header over the windows and doors that distributes the load of the wall
is a fairly solid piece of wood blocking that is the thickness of the
wall and is 8-10 inches tall minimum, but can be the total height of
the difference to the top of the wall depending on local codes, union
trade practices, and even if there is a second floor or not . so its
usually not possible to insulate it at all.

Hope this helps, Jimbo