Ideas How you would finish

Make sure your floor covering will hold up well when exposed to moisture. There is probably no moisture barrier under a garage floor, and that means a small amount of moisture will always be infiltrating up through the floor. You can add a moisture barrier on top, but it is nearly impossible to stop all the moisture. This will affect what flooring you choose.

You may want to tape a plastic sheet over a section of the floor and see how much condenses on the bottom of the plastic over a few days.

Bruce

With no insulation, and not built to habitable space requirements, the best you can do is be sure that the wood stove has the proper thimble and noncombustible surfaces behind it or below it to not burn the place down. No shiplap in other words. It will never be a comfortable space. But at least it can not be a fire hazard.

Thanks all. We were thinking epoxy on the floors.

Epoxy burns. Non-combustible required.