I have done this a few times when there were code compliance cases. The owners had asked or been told how to get the place back to at least a “grandfathered” status and then did everything while remodeling and then got signed off with periodic inpections.
I also demolished and entire house and did not pull permits for the demo but instead submitted prints for the new house which included that the scope of the work was to remove and replace existing house.
I suggest work with the building department to get their blessings unless it is just a situation of really small crappy additions where the old house footprint is obvious.Maybe they won’t want to be involved at all, but it is worth finding out, anonymously at first if you want. Then you decide how to go about it. Keep in mind a licensed contractor who will do it without verifying permit requirements or just says that it doesn’t matter, puts out a red flag as to how they will treat you.
You have possible obligation to discuss major changes to a house with your lender(if there is one). I haven’t met people who have done this unless they wanted a cash out refi for a remodel.
