In Floor Heating Over Concrete Slab

Hello,

I want to put in floor heating in my mud room which has a concrete slab for a floor. I am worried about heat loss into the concrete and condensation because two of the four walls are exterior walls and the largest wall is facing the north along with the door. I live in Wisconsin so I worry about frost making it's way into the concete slab and sucking the heat out. I do have 3/4" foam insulation on the outside of the foundation cinder blocks and 2" foam insualtion on the inside of the foundation cinder blocks, but only about 1 foot down.

Can you put some kind of insulating underlayment down first to help with heat loss or is this just a bad idea?

I appreciate any help I can get.