Our sewing studio is in our lower level (daylight basement). We were flooded in 2007 during a 100 year flood, replaced footing drains, reinstalled laminate flooring (Pergo) and again had serious water intrusion in 2012 from neighbor's water main break. Instead of laminate we went with vinyl planking. Easy to install (use the click kind for basements, garages), comes in many colors, if you do have water intrusion it can be removed, dried off and reinstalled since it is 100% waterproof. I concur that footing drains are needed and a permit will be necessary for electrical. Be sure and check with you insurance agent regarding coverage since the garage will have changed purposes and you want to make sure your machine(s) are insured against theft, fire etc.