Our water heater is in an interesting location. It has it's own little closet on the exterior of our house, about 4 feet up from the ground.
Zach removed the old water heater and prepped the space. First, he insulated the interior of the closet and sealed everything off with silicon caulk. The kitchen pantry shares a wall with the hot water heater closet, and this has helped quite a bit to keep the heat out and the pantry cool.
The old water heater didn't have a pan, and the plywood platform it was sitting on had rotted over the years from small drips here and there. Zach ripped out the plywood and reframed the base before adding a new platform.