Hi
Have solid wall with render on outside fitted years ago, seems OK condition,,, and new French doors just added on other wall have frame of 63mm. Hence total depth of insulation must be less than that.
I was thinking 50mm batton, 50mm foil PIR in between, then 12.5mm plasterboard on top, with dpm strip behind battons, that work?
Had electrician suggest dab n dot then insulation plasterboard on top, but that seems more likely I'll mess up.
