Glen: the shelter is a framework of saplings with large & small pieces of old canvas placed on top. Baling wire was used in some sections to join intersecting saplings and make it more rigid. Heavy snow had collapsed much of it when we first walked in, so we had to shovel it off and out. We placed notched poles down the middle to re-shape it and hold it more rigid. At one end there is a fire pit with a large opening above it to let the smoke out. Leaves are banked around the outer perimeter to keep out the drafts. We cut pine boughs for our beds, and then placed our bedrolls, including the concealed self-inflating air mattress, on top of that. You are so right about being acclimatized to temperature! Several of us were talking about life in the 1700's and we decided that NO one lived in a home where the temp was kept at 70 degrees, or even 65, so people were a lot more used to lower temps.