Re: Fireplace Brick problem
Was the original fireplace built as a wood burning unit, then converted to gas at some point. I would guess there are firebrick already in the firebox. But the real question should be is the flue built properly to burn wood. It should be built with clay flue pipe.
I would call in a certified chimney sweep to inspect and evaluate the current system. He should be able to tell you the condition of what you have & if it can or should be converted back to wood burning and what modificatons if any need to be done.
It isn't worth risking a fire not to have a pro look at it. Converting to a substandard wood burning fireplace may not be covered by your insurance if a fire occurrs.