I was advised to leave the furring strips that are nailed to the floor joists up. I don't want to nail dry wall to them. Am I wrong. They are perpendicular to the joists and only 1 1/4" anyway. Thats not much to nail the edges of the drywall. Also, the walls were constructe like this; furring strips nailed vertically on 16" centers, 3/4 foam insulation between them, coverd with clear poly sheeting, 3/16" paneling. There looks to be some (very little) mold. Can I just frame up 2x4 wall and drywall for new wall.