One thing i noticed between a shack with the floor insulated and not insulated is the uninsulated floor one the water and slush etc. will freeze to the floor, where as the insulated floor shack the stove heat will melt and eventually dry the floor.( without having to have the stove burning so hot you can't be in the shack. )
were building a permie this year me and some buddies were are using 3/8 and 1/2'' plywood for the walls and floors, with 1 1/2 foam insulation. a guy i use to work with build one like that and it stayed nice a toasty in there. look around on kijiji for materials thats what we did. found 30 4x8 3/8 plywood with the 1 1/2'' foam for 100 bucks... cant beat that price.
You just cant go wrong when you insulate... costs a bit more at first but the savings on heat soon catches up with costs.. and the comfort of angling without all the bulky clothes and with bare hands is well worth it.