[Blackie]

I'm taking a three step approach to this.

The first step was stop the heat getting in by insulating the garage door. I added a "radiant barrier" on the inside of the door. This was a simple DIY project that took about 3 hours and cost $50.

This step was completed about a month ago and seems to have dropped the temperature quite well. I am waiting for the hotter weather to confirm how helpful this really is.

Insulating the attic above the garage would help a lot but we use that space for storage so can't do it.

The second step was to "vent" the heat from the garage. I'm testing this by leaving the attic stairs open a few inches. If this proves worthwhile I may add vents (and perhaps a fan) to the garage ceiling.

The third step would be to add a solar roof fan in the attic to further vent the hot air. At this stage I'm not doing this and there is information that this "may" not be a wise thing to do.