I think the downstairs is all finished, but pinning just in case. "We show two good ways to insulate and finish a basement or concrete wall. A wall saves space and a wall is easier to assemble and insulate. Both will create that snug extra room you need."
Finishing Foundation Walls: Insulated Stud Walls Best for: Avid DIYers on tight budgets How it's done: It's the tried-and-true traditional method: A vapor barrier and rigid-foam insulation are laid over foundation walls, followed by a stud frame and drywall. Watch a video of Tom Silva using this method to finish foundation walls. thisoldhouse.com