Hi. I have a two car garage under the master bedroom of my 3 year old home. Ceiling is like 13 feet. Two feet high concrete foundation and then sheetrock I suppose for the wall. Along the back wall of the garage, I'd like to construct a basic raised platform for storage of miscellaneous stuff like kids toys/sporting goods/etc. I'm thinking something very basic along the lines of 4 4x4 pillars topped with plywood or something. Not sure how high off the floor I'd want it; either 4 feet high where I can just reach up and access stuff or maybe 6-7 feet high that might require ladder access. How would I go about securely constructing something of the such? If it's basic enough, not too high off the ground, no overly heavy storage items, and I include some cross-bracing on 3 sides of the frame, could I get away with not fastening the frame to the wall? Another possible feature to add might be a set of stairs from the garage floor to the raised storage area (precut stair joists from HD or Lowes). Thanks.....