How big can my pole barn/detached garage/minibarn/pool be?
The maximum size allowed is specific to each individual project. In general, the best rules of thumb are that any one accessory structure may only be 75% of your total main floor living area and the total square footage of all accessory uses (patios, porches, attached garages, minibarns, pools, etc) must be less than 99% of your total finished living area. These are called the 75% and 99% rules, respectively. The 75% rule has only one exception, which is for a detached garage (with a maximum size of 24×30) where the square footage exceeds 75% of the main floor living area and the detached garage is the only accessory structure. This exception allows the maximum size to be no greater than the main floor square footage.
