I have recently bought an old post and beam home. It is now just basically a frame on a slab. The home came with no insulation at all. I was wondering if it would be possible to fix EPS concrete panels to the exterior frame or even between the posts themselves. Would this be structurally sound? Would it be better to use OSB foam sips? This would provide reasonable insulation. The house is a two story rectangle and about 300 square feet.

jppie - it depends on how the original foundation id designed.
Are the posts carried by their own footings or is everything supported by the slab?
What type of eps concrete panels are you thinking of?

Would the concrete panels be heavy and hard to maneuver into place under the beams?

You might look into applying EPS to the outside and covering it with mesh and stucco (like a low strength SCIP). The inside could be covered with gypsum and the resulting cavity could be filled with sprayed cellulose.

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