SteveC wrote:
I don't get it, if I have everything sealed up by chaulking, where is the
problem here???

Please explain.

There is a reason carwash bays are made out of concrete or sheet metal.
There is No Way to perfectly seal a wooden-frame garage wall to make it
suitable for doing wet work in there. The water-resistant garage
finishes are for occasional splashes of rain and snow, and high
humidity, not actual streams of water. You will get mold, and the wood
will rot.

The only way to do what you want would be to backer-board the walls and
apply tile or waterproof panels, like a gigantic shower stall. Even then
it is unlikely to be waterproof for long, since a 20+ foot long wall
flexes a lot more than a 3-foot-square shower stall.

aem sends...