You really need to ask your local town official. The building inspector is the place to start.
Use a payphone in a dark alley to call, and use a fake name.
No really they are there to help,
tell them what you are doing, and ask what is covered under permits in your area. Some minor home repairs like painting and fixing a door do not need a permit. However once you remove the door jambs or change the door, that may require one.
Every town is different, go meet and greet.