Here's most of an answer to a similar (garage, not basement) question that I recently received from a local code official in another state:
"The 2012 International Residential Code (IRC) defines habitable space this way. A space in a building for living, sleeping, eating or cooking. Bathrooms, toilet rooms, closets, halls, storage or utility spaces and similar areas are not considered habitable spaces. The garage is a non-habitable space. If the new room will be a space used to store your hobby materials, finished products, etc., then it would be considered a non-habitable space as well. However, if you will spend time in the new room working on your hobbies, it will be considered a habitable space. This is an important distinction because a habitable space has many more Code requirements associated with it than non-habitable space.
As I noted, we review all residential projects submitted to obtain a building permit against provisions of the 2012 IRC. I cant list here all the Code requirements regarding habitable space as they are numerous; however they relate to fire protection between garage and habitable spaces, natural light & ventilation, heating, electrical, plumbing, and energy requirements for insulation in exterior walls and ceiling and for any mechanical system you might want to have installed. For non-habitable space, few of these concerns listed above are applicable.
I recommend that you obtain a copy of the 2012 IRC, perhaps at your public library reference section, and go through it to ascertain what is needed..."
Many jurisdictions have adopted the 2012 IRC. It can be reviewed on-line here:
I echo previous advice against making non-permitted permanent modifications. Doing so frequently causes extreme trouble when selling or attempting to collect on an insurance claim, not to mention increasing the real risk of injury or death. Temporarily installing hobby items using quick-disconnects, on the other hand, might be your best available option.