I have a log cabin in North Carolina that was built in 1980. It has 6-inch thick walls (curved on outside, square on inside). We are currently heating the house with our Regency I3100 insert located in a stone fireplace on an exterior wall of the cabin. The stove works great when the temperature is above 35 outside. When it is below 35 outside, we have trouble getting the house above 62 or 64. Anyways, I would like to improve the insulation in the cabin and my wife would like to add drywall to the interior side of the exterior walls (she wants to brighten it up a bit). I was curious if anyone out there has ever installed drywall in a log cabin. I was thinking of adding a 1-2" rigid insulation foam between the logs and drywall. If I did this, would I need to install a vapor barrier? If so, would I install the vapor barrier between the foam and logs or foam and drywall? The cabin sits on a basement with concrete floors and cinderblock walls (3 of the 4 walls are partially underground) . The basement is consistently 40 degrees in the winter time. The basement ceiling has fiberglass batt insulation that is somewhat poorly installed. We plan to convert some the basement to living space so I plan to insulate the walls instead of trying to repair the basement ceiling insulation. Any thoughts on this would be greatly appreciated.