If you plan to put a yurt up in a cold climate we STRONGLY encourage an insulated floor. An option we offer to our customers is a SIP floor. Below is the nitty gritty on our SIP floor option but in a nutshell : it's round, it's warm, it's simple.
SIPs or Structural Insulated Floor Panels 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, homes or commercial buildings. They often prove extremely cost effective for several reasons.
First, a SIPs floor can be deployed within several hours of having the deck framing completed. The panels arrive ready to install. The proper circular shape has been precut during the manufacturing process. The outer perimeter of foam has been recessed back to accept a full wrap of 3/4” plywood, which facilitates an extremely strong connection of the bender board. The bender board is the component that secures the yurt walls to the floor/deck.
Second, no decking material is required underneath a SIPs floor system. The panels are typically fastened directly to framing. The superior strength of the panels requires no reinforcement to span between support beams. This floor option provides an extremely solid base for a yurt.
Third, the SIPs floor is already insulated. A 4.5” thick SIPs floor will typically exhibit an R-value of 16, while a 6.5” thick system has an R-value of 25. A well insulated floor can dramatically increase the overall thermal performance of a yurt.