All great ideas.
Everyone keeps talking about a floor drain for washing. It's indeed a good idea, but don't forget about draining the foundation itself.
Plastic 4"-6" drainage tile is cheap insurance against cracking floors, along with compacted soil and a good compacted base and slow cured concrete along with a minimum of 4 inches...exactly, or more (being prefered). No 2X4 thickness jobs on my watch.
Tile both inside and outside the foundation and tie them together with a pipe going through the foundation itself. Keep downspout water flowing well away from the building.
This will hedge against cracking floors that you're so desparately trying to keep looking neat. Nothing worse in a new home than to see a nice race deck or sealed floor with cracks in it.
Why the tile the inner parimeter of the foundation? Sometimes, though rare, water can find its way into areas because something upstream disturbed the flow of underground water. When this happens it will find the path of least resistance and sometimes that is up. I've seen it push through 20 feet of wet concrete. If this water happens to find its way under your floor, you have a way of keeping it dry by mean of an inner "tube" (pun intended).
By the way, as long as we're dreaming here, there is no place for a space heater in my garage (too many fumes and dangers associated). My uncle blew the roof off of his garage, well his specially hired mechanic did, and roasted a 1963 Vette that he'd bought new. Melted her to the ground, blew the roof off, and knocked the building way out of square. Found out a fuel line was leaking...found out the hard way.
