I've got a 1953 plain fireplace, floor to ceiling, enamel-painted brick. Would like to add mantel-surround, stone tiles near fireplace opening and box in fireplace above mantel with drywall. These are rough bricks -- surface isn't very flat or uniform. What's the best way to level out the fireplace for drywall? Do I need to first attach steel furring strips? Should I strip the brick veneer first and start over?