Hi,
I’m looking for a viable option to add insulation to a brick veneer over 2×4 framing structure. Some Pink fiberglass in the cavity.

There is black plastic sheet under the plaster.
I would like to leave the plaster in place for cost savings and fire separation.

Can I add a thin layer of foam or mineral wool 1-1.5” on top of the existing plaster, and then new drywall? With or without strapping?

Location Kingston Ontario.

Thanks!