Ken, Excellent question! Thank you for your interest.
Bobby, thank you. You found probably the best photograph in the long topic. I have to go plodding back through the pages myself to find things myself. I'll post photographs I just took today and answer.
To get you up to speed, this room was is an addition my in-laws put on the back of the house. The layout is on the basement level. My in-laws removed a deck on the upper level and had a 12 x 12 sunroom built, and this room to them just basically supported the sunroom. When we moved here our older daughter was in college and she made the room into her art studio. So the photograph Bobby found on page 7 shows the room once our daughter had married and moved everything out. She had put the upper shelf in. It is just the white finished 8" shelving you can get at Lowes or Home depot. I suggested she use the brackets shown in the first photograph to attach it to a bulkhead that encases the furnace intake and exhaust pipes that come from the combination furnace/laundry room in the main part of the basement.
This photograph shows the bulkhead as best as I can do it. I have the brick wall that is from the back of the original house and I removed the window to let air flow in from the laundry. I'll contend with the brick wall side of the room later.
So from the bottom, it looks like a 24" deep shelf, where actually it is only 8" deep.
I hope that clears up the confusion, but please ask any questions that come to mind. Thank you.
