Dog door advice, question and install

[Lurch]

Make sure the silicone you buy is the Paintable stuff. Also before sealing use some of the stuff that goes between a window and the exterior wall. I can't link from my fire,or I would.

I think you are talking about backing rod and yes stuff the gap full of it or the chalking will fail. Also you can get a device that will trace wires in a wall.