I want to build a wooden balcony in my living room. The height of the room is about 9 feet, while I intend to have the balcony at about 6 feet. The length of the room is about 12 feet and the depth of the balcony will be about 3 feet. My problem is that I don't want any columns along the beam that will span the room. Would that be possible? Could I put some posts to support the beam at each end and bolt them to the concrete block walls at either end? What size beam would I have to use? The maximum weight that will be on this balcony will be about 200 lbs.