My garage is 24' x 25' and constructed from cement blocks. The roof is new, 16' garage door is insulated. It is very cold in winter with no insulation. I'd like to get the rafters foam sprayed to retain the heat. I'm using a 25k btu kerosene heater that works pretty well. The machine shop area had an electric heater. Now that I've had heart surgery last month, I may be around for a while. I'm considering going out the back of my garage 10'- 12' with a radiant heated slab. I will move the entire machine shop into it. The low hanging loft will be removed and moved up as well as be shortened up (so I don't save too much crap). Wall construction can be wood and vinyl siding with good insulation all around. Heat might be a pellet stove in the new area and a 220v electric in the old area.