The Sommer house is the archetype of a Hajjar house. It is a shoe box built into a hillside and it has a quite low pitched roof. There is a somewhat hidden entryway which is midlevel with the two stories of the main house. A flat-roofed garage is at the entry level and connected to the house with a breezeway.
Floor to ceiling windows are strategically placed to focus occupants on an outdoor view and/or spread natural light throughout the house. There are fairly large overhangs at the end of the roof to shade the windows beneath in the summer and permit entry of direct light and warmth in the winter. The house is built on a slab at ground level with radiant heating pipes buried in the concrete. On the second level, the radiant heating pipes are in the ceiling. (Most systems have held up well, but a few have been converted to electric baseboard heat.)
Rather than a hallway to the bedrooms, the hall is expanded into a sitting room for reading or games. This often results in rather smallish bedrooms, as typical of Frank Lloyd Wright. Also Wrightian, there is no attic or basement for storage.