Went through that exercise a couple years back. Even though my workshop (garage) is attached to the house by a breezeway, the insurance company categorized it as a separate building. So regular homeowner's policy does not cover it. My only option was to take out "inland marine insurance" and that was prohibitively expensive. I am not worried about large equipment (saw, planer, bandsaw, milling machine, lathe), since that stuff weighs way to much to be moved during a burglary. But I would take a big hit loosing hand tools and portable power tools. Also would be nice to have some insurance on tractor and skid steer, since that equipment can be driven offrather easily. But again it was just too expensive.
If someone finds a reasonable rate, I'd be very interested....
Thx
Bernhard