JANUARY JLC 1998
ost windows and doors are manufactured to
fit the 41/2-inch-thick walls that were the
norm 20 years ago. Since the early '80s,
when 2x6 exterior wall studs became commonplace,
to fit 61/2-inch-thick walls
have also been made available.
But the exterior walls of today's houses often
include additional materials — a layer of rigid insulation,
a double layer of 5/8-inch fire code drywall between
the house and an attached garage, resilient channels to
reduce sound transmission — that add another inch or
more to the wall thickness.
This isn't much of a problem with windows, because
they can be mounted flush with the exterior sheathing,
with extension jambs applied on the