<a href=showthread.php?s=&postid=7591531#post7591531 target=_blank>Originally posted</a> by mlukason
Neither screws nor nails should support weight. Make sure that the weight is supported by vertical pieces. The screws and nails are to keep the lumber together only. You may consider using plywood...it is relatively inexpensive very strong and (in my opinion) is better looking than 2x4's. I have a few images posted in my gallery that my give you an idea with plywood.
Sorry, I haven't seen the cinder block design.
Good Luck!