Mike writes from Canton, Georgia: "Got a newer ranch house on a full unfinished basement. The house is rectangle in shape. I want to finish the basement. One short wall is all poured concrete (below grade). The opposite short wall is all 2x4 (above grade). The long walls are a combination of concrete and 2x4 studs. Mostly below grade i.e. concrete. Now it gets tricky. The poured wall is about 10" thick which causes the 2x4 wall to expose a ledge because the 2x4 wall is flush to the outside. Thus I plan on building a complete 2x4 wall so that I can have a truly flat wall for the finished basement.

Doing that will give me about a 13" cavity above the poured wall and a 2x4 cavity along the poured wall.
1) How do I insulate this hybrid on the 2 long walls?
2) Do I build out the short 2x4 wall to something thicker to balance the insulating of the entire space?
3) Does the existing paperbacked insulation that is in the main floor (basement ceiling) needed to be removed?
4) Does that floor (ceiling) insulation paperback need to be removed or cut open?

I already scanned through the previous 12 months of questions. Didn't locate obvious answers."

Answer: 1) The two long walls should be insulated just like any exterior wall. We recommend Kraft paper facing rather than any plastic since the vapor retarder will be in a high moisture content area.

2) Building out is your discretion. Building out will let you increase the R-Value of the wall but keep in mind it will also reduce the living space in the room.

3) No. You will still benefit from the acoustic value between the floors.

4) No. Keep in mind that if you are finishing the basement you will need proper air handling or a dehumidifier to prevent moisture problems.