Laundry room in our house is at the lower level of the house. It has a concrete floor with uneven surface and fair amount of cracks. I would like to put vinyl over it. I hope to keep as much head room as possible. My plan is to start with some kind of styrofoam plates? (1 in. thick of so). Than 3/4 in. t/g playwood, drill holes and use some kind of concrete fasteners. Vinyl will go on top of this. I think that such design will give me relatively smooth and varm floor. Does any one had any experience with this type of design? What kind of concrete fasteners should I use? What about vapor barier between concrete and styrofoam plates? Any suggestions will be greatly appreciated.