Plenty of business cards say “no job too small.” Builder Dan Upton and architect Jeff Shelton could reasonably have “no lot too small” printed on theirs. Not that either of them specializes in small projects — but they did complete a house (1) on a 20-foot-by-20-foot lot in Santa Barbara, Calif.

Originally the lot was two parking spaces in the alley behind Neil and Sue Ablitt’s dry-cleaning business. After living on a boat for several years, the Ablitts decided they were ready to move into something larger, so they hired Shelton. He designed a four-story 699-square-foot home with one room per floor and a rooftop patio with an outdoor kitchen. The 58-foot structure has a grid foundation on caissons that extend 45 feet below grade. The shell — walls, floors, and roof — is made from reinforced concrete (2).

Located in a commercially zoned area, the house is subject to strict fire standards. Since the setback is only 6 inches and the surrounding lots may eventually contain buildings, only the windows on the front wall could be operable. The ones on the sides and back are fixed panes of 1 5/8-inch laminated glass — technically not windows but “transparent walls.”

The finishes are as unusual as the structure itself; almost nothing is stock.

Custom-made tile covers most of the interior and parts of the exterior (3,4). A 108-foot walnut rail snakes up four flights of stairs, passing through a room with keyhole-shaped windows (5) on its way to the rooftop patio, which has built-in seating and intricate wrought-iron guardrails. The view is great, but to see it you have to climb 72 steps. — David Frane