We are putting an earthen floor in an addition that we have built onto our home (original structure is a 1960's brick rancher that we are changing quite drastically). It's approx a 20'x20' room that will be the family/living room for our 6 person household. We'd like to put a couple of floor outlets in the middle of the room so that we can plug in lamps, etc, to avoid having cords that our little ones and aging parents will certainly find hazardous. Anyone have any experience with or knowledge of what materials we can use to allow the electrical work to be safely housed under the earthen floor? Thanks in advance.