I'm not sure what you are calling normal flooring. but all I can find out about the link you provided appears to be a company which applies the coating to an existing concrete floor. I would suggest that you consider contacting 2 or 3 reputable construction companies in your area. Provide them with at least a rough layout of your garage size then ask them to refer you to a contractor who specializes in concrete slabs. They may ask you for architectural drawings. For sure your local municipality will require you to contact the building and zoning commission for permits before you will be allowed to build your garage