There is a decorative (non-structural) beam that runs the length of our living room ceiling. The ceiling is about 12ft tall. The beam is supported by two carriage bolts driven through the beam in the middle of the room and into the attic. A steel cable is connected to the top of the bolt, attached to a turnbuckle and then secured to a rafter. Only one of the bolts has a turnbuckle and the cable on the other bolt is simply wrapped around a nail in a rafter and is no longer taught. A previous owner installed two ceiling fans dramatically increasing the load on the beam. Over time the beam has begun to slip creating a gap up to half an inch along the entire length of the beam. What is the best way to secure the beam and reduce the gap?