SIPS (Structural Insulated Panel System) are a composite material that provides the benefits of insulation and structural performance in a single building product. They consist of a layered sandwich of materials. The top surface (what is the sub floor/walking surface) of the yurt is 1/2" OSB. The middle layer is EPS (expanded polystyrene) insulation, and the bottom layer is ½” OSB. This simple sandwich panel forms an amazingly strong insulated panel for floors for yurts. All panels are pre-cut to click together in a matter of hours to form a perfect circular platform for your yurt.