Just need an opinion or two if what I'm doing is an acceptable procedure. I plan to install a partially recessed medicine cabinet on an exterior wall. There are is no wiring or plumbing in the way. I need to notch out one 2x6 stud. I plan to remove 2.5" of the stud, 30" high. This will leave 3" of the existing stud intact, which is almost equal to a 2x4 so I presume this will be ok. I plan to box in the opening with 2 x 6's, carring the top and bottom pieces over to the adjacent existing studs. I plan to install 3" of rigid insulation behind the cabinet, giving an R value greater or equal to the existing R19 fiberglass. I'll caulk around the insulation and install a moisture barrier over the surface and sides. Any thoughts on this, suggestions, etc.?