Not a lot of specialized building permits or restrictions up here. Some of the bigger towns like BTV have layers of code enforcement etc. but in towns like mine it’s mostly zoning on the town level. As long as I’m not expanding the footprint, I don’t need anything. None of the finishing in the basement, bathroom renos or kitchen reno required anything. As long as you stay within the setbacks for the zone you’re in and it’s an allowed use, all you need is a building permit which is $90. Now, there are state permits for some things like septic design. Storm water runoff is also regulated on the state level but I think that’s for developments etc. the state also has some strict land use/development laws for lots over 10 acres.