Just want to make sure I'm not creating any potential issues with this set-up:
I am building an attached garage onto the front of my house. I have some 2" Type IX EPS leftover from another project. The shared wall is 2x4 construction, originally with R-11 kraft faced batts and 1/2" of foil-faced poly-iso foam (no structural sheathing). The room on the house side has a vaulted ceiling with site-built scissor trusses. Because of the way these trusses extend into the wall space on the house side, there was a ~6" tall hole at the top of each cavity connecting the wall cavity to the attic... which I'm thinking doesn't do much for the R-value of the wall (air penetration).
First thing I did was cut pieces of 2" EPS and use them with canned spray foam to seal the wall cavities off from the attic space. And also removed the mouse tunnel/poo/pee ridden R-11 batts and replaced with new R-13.
Then I squeezed a fat bead of foam adhesive on each stud/plate and secured the 2" foam, leaving a 1/2" gap between each sheet and filled that with spray foam for a good seal.
I then installed 1/2 drywall directly to the face of the EPS. This is also to function to some extent as a fire block, as it has no penetrations.
What I am planning to do tonight is build an additional 2x4 wall on the garage side 1/4" off of that drywall. This is to house the electrical outlets. My intention is to spray foam the perimeter of each cavity and install unfaced R-13 batts in this wall. Any issues with that? I don't think so since the batts with be unfaced; but it doesn't hurt to check. The wall is getting built regardless; but I don't have to seal and insulate it if that will cause problems having the foam/drywall sandwiched between two FG walls (only the inner wall being faced, though). Thanks!