Hi, I have a woodburning fireplace in my Carmichael, California home. It is located in the family room which was an extension built in the early 1970's (I believe 1972 or 1973). The foundation is slab, and the fireplace is made (or at least covered entirely) with "recycled" bricks. The outside hearth is raised, about 15 inches or so from the floor, and extends out the front of the fire place about 18 inches. It is 9 feet wide. I am currently running speaker wires and other A/V wires around the hearth on the floor, which doesn't look good. I can't go over the mantel since there really is no mantel -- the bricks run straight up to the ceiling. I would like to go through the (outside) hearth (far away from the fire) by drilling a hole on the left side near the floor, and on the right side near the floor. That way I can run the wires through the hearth from left to right as opposed to around it on the floor. The question is, what's inside the raised hearth? Is it hollow? Is it built up from cinder blocks? Did they fill it with concrete or rubble? I drilled a small test hole on one side in the grout, and felt something harder behind the brick, about an inch or so, and then, hollow. When I put a stick in the hole, however, it gets stuck a little further in. In case it helps, when I looked inside the fire box, the inside hearth sits lower than the outside hearth, by exactly the thickness of one brick. Before I drill deeper holes or a hole on each side to see if I can shine a light through, I figured I'd better ask the experts... Thank you. -- Paul J.