Our house is a bi-level, with brick on the bottom and siding on the top. We took the drywall off the two outside walls of one of the bedrooms downstairs and discovered NO insulation at all. Simply the concrete foundation up to half and then black scratchy paper that has the brick behind it. The top half as 2x4's along the black paper and the bottom half had two horizontal strips of wood that were used to attach the drywall to. I think we will be fine putting R-19 in between the 2x4's and an .5 to 1.0 inch insulating board along the concrete. That, along with a new energy efficient window, should be plenty for this 10 x 13 room. Rob wants to build into the room 1.5 inches for those two walls, putting thicker insulation in between the 2x4's and a 1.5 - 2.0 inch insulating board along the concrete. We will be insulating the rest of the house as well .. we'd like to know how far we should go.