[RWebb]

call the city or county - at least here, they are very helpful to a DIYing homeowner.

since the reqs. vary you need to talk to YOUR permiting authority (they are all based on a uniform code but each can - and often does - modify that code)

the advice re protection from a bad contractor and from insurance co. who might disallow any claims is good advice; likewise the ability to ever sell or perhaps even refi the house.

Bldg codes are like stop signs - at 3 am you really don't need to stop, but usually you do. The problem here is you can't really tell whether you can skirt a certain code provision or not - even if you get away with it, it can come back and bite you later on.