Our house has an old brick and mortar fireplace with a brick face from the floor to ceiling. We are planning on covering the brick and texturing and painting over it. The current plan is to attach some 2x4's to the brick and lay drywall over the 2x4's. We are also considering building a frame for a mantle and drywalling over it also. My question is should I be using cement board instead of drywall? I know there are codes that involve how close combustible materials can be to the fireplace opening. Does cement board have the same restrictions? What about the texture and paint? Anything else I should know?