I definately needed a lumber rack in my new small shop so I got to looking around the internet at other people's ideas and builds and most of them seemed pretty complicated or they protruded out from the wall to much for my small shop.
I came up with a simple but strong design that doesn't force you to sacrifice space nor does it take alot of tools, materials, or complicated jointery to build. In my small shop I am trying to put alot of things on wheels and this lumber rack is not built all the way to the floor so that I can roll tools underneathe it.
So take some time to watch this video and build yourself a great lumber rack.
I do consider this a meduim duty lumber rack but you could easily add two more uprights with supports between these making them 16" on center rather than my 32" on center. This would add alot of extra strength is you decided to load it up excessively.