cpfrog

All the above suggestions are great.
I too like smooth floor for picking up pins, and moving my chair, and general sweeping.

If it was my basement, I'd also buy a good DE-humidifier to remove excess moisture in the air. That way nothing will "smell" and there will be less of a chance of mildew, esp. with all the fabric you'll be storing! :-)

Might want to also invest in large plastic totes for some storage over that floor. ( What if you had a flood of only a couple inches???? or if the elect. went out and the sump pump didn't work? )

Cold? an elect. floor heater or gas wall heater; a rug under your feet; a warm sweater!
Hot? a ceiling or floor fan; a window AC if it would fit?

Good luck and happy sewing.