I would like to know how to insulate my basement walls the correct way. I have 8ft.poured walls in my basement i left about a 1/4 to 1/2 inch air gap then framed up the 2x4 walls i put R-15 kraft faced on all poured walls with a 6mm vapor barrier ,all the other walls that are on the interior of the room are R-13 kraft faced i thought to put the 6mm vapor barrier on the backside of the stud wall too is this overkill.:huh: