Need to talk to building inspection! My guess is, the county building inspectors aren't checking on Trulia like all of us realtors and buyers. We aren't qualified to give you the permits you need and give you the specific requirements. Go to the Ottawa Co. authorities- you'll find them very easy to work with! It will be worth your time so you don't start renovation and realize you aren't up to code and most importantly, putting your family/friends at risk if they would be sleeping in a basement without proper ventalation, egress etc. A reputable contractor in the are would be able to walk you through the process also. Good luck!