In addition to drainage, you should consider the moisture/humidity that you will be introducing into the garage. Tools will rust and you may get mold in your walls/rafters if you don't have some sort of humidity control (exhaust fans, etc.). Washing in cinderblock "car wash style" building building is very different from a home garage consisting of insulation, drywall and wood which was designed to be fairly airtight. I'm sure you can do it, but you will need humidy control.

 

good point, in the winter that shouldnt be a big issue, but in the summer that would be the main concern along with drainage

 

I just bought a space heater to warm up the garage, and I'm going to just give the car a basic sponge bath (damp sponge, wipe down carefully, rinse sponge in bucket, repeat). No drain in floor so I'm sure there will be some water left over, but I'll do my best to keep it to a minimum.

Trying it for the first time on Sunday....

 

ooooooooo sounds like a swirl fest, make sure the first bucket is full of really sudsy , mild auto wash and use a second pail to rinse the sponge in before going back to the sudsy pail....... hate to see you get swirls and mild abrasions on such a new car............ Cheers