stylistic:tone, quality:correction, linguistic:paraphrasing, information:extraction
Building materials

Sumerian masonry was usually mortarless although bitumen was sometimes used. Brick styles, which varied greatly over time, are categorized by period.

The favoured design was rounded bricks, which are somewhat unstable, so Mesopotamian bricklayers would lay a row of bricks perpendicular to the rest every few rows. The advantages of plano-convex bricks were the speed of manufacture as well as the irregular surface which held the finishing plaster coat better than a smooth surface from other brick types.

Bricks were sun baked to harden them. These types of bricks are much less durable than oven-baked ones so buildings eventually deteriorated. They were periodically destroyed, leveled, and rebuilt on the same spot. This planned structural life cycle gradually raised the level of cities, so that they came to be elevated above the surrounding plain. The resulting mounds are known as tells, and are found throughout the ancient Near East. Civic buildings slowed decay by using cones of coloured stone, terracotta panels, and clay nails driven into the adobe-brick to create a protective sheath that decorated the façade. Specially prized were imported building materials such as cedar from Lebanon, diorite from Arabia, and lapis lazuli from India.

Babylonian temples are massive structures of crude brick, supported by buttresses, the rain being carried off by drains. One such drain at Ur was made of lead. The use of brick led to the early development of the pilaster and column, and of frescoes and enamelled tiles. The walls were brilliantly coloured, and sometimes plated with zinc or gold, as well as with tiles. Painted terracotta cones for torches were also embedded in the plaster. Assyria, imitating Babylonian architecture, also built its palaces and temples of brick, even when stone was the natural building material of the country – faithfully preserving the brick platform, necessary in the marshy soil of Babylonia, but little needed in the north.