Brad...4 comments on 2 similar workspaces under my lower deck: The surface of one space is a salvaged sink countertop (5.5 ft long, 2ft deep; with a 2ftx4ft sheet of Homasote covering the opening for the sink) supported by 2 salvaged wall-mounted kitchen cabinets--12Dx15Wx30H inch at one end and 12Dx30Wx30H inch at the other. 1. I had to carefully position the cabinets so there was enough space between the cabinets for my knees or to push in a chair. 2. I plugged in an extension cord, so I wouldn't have to crawl under the countertop every time I wanted to use the wall outlet behind the workspace. The other workspace was initially made with a 15x40 piece of Homasote resting on top of a 15Dx40Wx25H bookshelf, which was located against a wall between a corner desk and a 15Dx24Wx30H bookcase. 3. I didn't like the low level and that the lack of knee space prevented me from drawing my chair close to the work surface. So I took a 24x66 inch sheet of Homasote, supported one end on the desk, turned the 30 inch high bookshelf 90 degrees to the wall to support the other end, and stacked some braces on the 25 inch high bookshelf to support the back half of the Homasote. 4. This arrangement gave me a long working space as well as great knee space, and someplace to store my wheeled stool when I wanted to use the aisle during operating sessions.