[Chevette]

One more thing, Zammer mentioned a drain, "if allowed". Make sure you build to code. Some of the comments so far have code issues. For instance many cities/counties/towns/etc require fire rated finishes such as fire rated drywall (especially if the garage is attached to the house). Welding, grinding and cutting with a plasma cutter or Oxy-Acetylene are obvious fire hazards and in many locals can require special attention to codes. In many areas "pits" not not allowed. You could potentially build a fantastic garage with many code violations. If in the future your garage met with disaster such as fire, or other damage, the insurance company will do their best to get out of paying for rebuild/repair. They can used a code violation to get out of paying your claim. Check your local code requirements.