You may want to check into a Polarshield emergency blanket, which can be had for 10 bux. It will be much stronger and easier to handle than a mylar space blanket. It has grommets and can be used as a ground cloth, shiny side up, blue side down. <br><br>Your roof would be a GI poncho or tarp. <br><br>Another option would be the emergency bivy bags such as the Land/shark or Thermolite bivy from Adv Med kits. The latter is only 20 bux, both are very easy to use.