Ancient Sumer: In the cities of ancient Sumer, whether they were rich or poor, every family had its own house. The rich had large wide houses, the poor had narrow houses. All of the houses were built at least three stories high. The first floor was an entryway and courtyard. Children played here, small livestock was kept here, and if the weather made it possible, meals might be cooked here. The next two floors were where the family lived. Their sleeping and sitting rooms were on these two levels as well as food storage. The roof of the house was flat. The people treated the roof as another floor. During good weather, people would cook and eat on the roof of the house. This got everyone up away from the streets, yet still out into the open air.
Ancient Babylon: In Babylon, as in Sumer, many of the houses were designed with three stories of living space. All had flat roofs. Some roofs were designed with four wall for privacy. Some had grape arbors for food, privacy, and shelter from the sun. Even the very poor, who lived in tiny townhouses, typically had three levels of living space. The courtyard, or first floor, in each house was very important. Behind the front door, a visitor might find a tiny garden and domesticated animals such as chickens. In Babylon, people threw their trash out their front door. Now and then, the city covered the streets with a new layer of clay. This buried the trash, but that made the level of the street higher. People had to build steps down to their front door, or fill in the space between the new streets and punch in new doors.
In both Sumer and Babylon, houses were built out of cut sandstone blocks or mud bricks. In the poorer sections, they would share walls to cut down on construction costs. In the richer sections, the houses stood alone. All of the houses were clustered around the ziggurat to make it easy to get to the temple and to leave offerings to the gods.
Ancient Assyria: Buildings in Assyria were always rectangular. The homes had doors but no windows and no internal staircases. They got away from clay bricks and built their homes of stone. The flat roofs were thick layers of earth on top of strong beams. This made the houses nearly or actually fireproof, and places of security. The Assyrians were warriors, and their permanent homes reflected this far more than the homes of the Sumerians and Babylonians.