I have read here that it is best to put the vapor barrier above the rigid foam insulation.  I need some advice on the best way to do it with in-slab heat and steel reinforcement.  5600sq ft house at 8500 ft, in Colorado.

We are using type II EPS as it is more environementally friendly, but I am a little fearful that over time it could become saturated.

Question:  Can I put a 10 mil vapor retarder under the EPS to protect it and then put another one on top of the rigid foam to protect the concrete, following the recommendations of the “Placement of vapor retarder for radient heat under slab” article.  Corrolary question:  If this is stupid, can you please tell me why?