I have a steel frame workshop with metal siding that I want to add a window unit A/C to. In order to do that I will have to cut a window sized hole in the side of the building and with that I will need a way to trim out/seal said hole.
I have found several guides online for metal siding trim before it's up but have found nothing for doing it in place. Will I have to pull the siding down or is there a method for doing this in place?