Locating the antenna that close to your garage, even using standoffs, will cause the antenna to detune and not work properly. It should mounted away from structures, local noise sources, or other metallic objects that can affect the tuning, radiation pattern, and SWR.
If you have a small lot, you may want to consider alternative antennas such as the Hy-Gain AV-640 or Cushcraft R8. Both antennas use elevated mountings and include a set of short radials that act as a counterpoise.