There is no height requirement in the NEC code book. You can pretty much put them where you want. I usually install them at 44" to the top of the box except where there is a work bench and then I install them 48" to the top of the box. That is just what I have found to be a good height. The choice is yours. Remember that all garage outlets must be GFCI protected.
4 inches
Can the garage floor mats help with the condensation and garage floors
the height will depend on local building codes' requirements and also what time of outlet (ground, countertop for kitchen and bath, and ceiling such as in garage doors). Typically wall outlets are 16 inches on center from the finish floor.
Either the garage door would need to be cut and adjusted in height to conform to the floor, or the floor would need to be modified to conform to the door. If the door bottom is near level, the floor should be built up to meet the door. If the floor is level, there are serious issues with the door. Consult a garage door installer.
My garage floor needs a new coat of paint. What is the best garage floor coating paint?
This is not something you will want to do twice. Consult a residential engineer.
rustoleum garage floor kit.
There is no code ruling on this. I set mine 12" to center. If you are putting in a new outlet in an existing home I would suggest you just match it to the height of the rest of the outlets.
You can basically use anything on a garage floor, but what I would recommend is that you get garage floor tiles. The are durable and easy to install. The best thing about it is that it makes the garage look better.
My garage floor is quite dull looking. Are there any companies that would do a garage floor coating to make it look nicer?
When looking to purchase garage floor mats they can be found on a few online websites for sale. Amazon are advertising low prices on garage mats. The Soft Floor website also has a range of garage floor mats for sale.
Coating your garage floor with epoxy seal paint will provide you with the best clear finish. For a better finish, coat your garage floor multiple times.