On Mar 15, 12:34*pm, Limp Arbor wrote:
Almost ready to start the rewiring of my house, just need to finish up
my plans. *I am probably going to go with plastic old work boxes that
are 3.5" inches deep in most situations.

This is going to leave me with 3/8" at most between the back of the
box and the sheathing on my outside walls(3/8 drywall).

Any reccomendations on how to insulate behind the boxes and around the
sides of them?

Use a latex spray foam like that recommended for window installation
at the back of the box. Expansion won't bother the box installation.
Then cover the remainder with fiberglass bats, whatever.
Do you really have 3/8" drywall exterior sheathing?

Joe