Photo 4: Spiral Stair to Addition On the main floor of his house, a large living room had just enough space for us to sneak a spiral stair down into the “crawlspace” addition. On the uphill side of the addition there was only a foot or two below the new floor, but on the outside wall after the floor was added there would still be eight or 9 feet of height below the new floor. The owner was pleased that he was able to maintain a clear span space below the addition for storage. And we're also able to access crawlspace storage area on the uphill side of the addition at the same level. Photo Credit: Indivar Sivanathan