Roman architecture was very complex. It was influenced by the geographical, political, economical and cultural factors. Knowledge of roman architecture comes from remains left around the Roman Empire. Another source of information is from records of public writings on structures. The book called De Architectura, written from Vitruvius, describes in detail information of almost all aspects of roman architecture. This book was limited because it was written based on Greek modules and was written at the beginning of creative roman architecture. .
Romans used many different types of materials to build structures, such as wood, volcanic rock, and brick arranged in mosaic patterns. Unburned bricks faced with stucco were also used. However, the wealthy citizens of Rome only used these. The use of marble was usually decorative. The use of stucco over unbaked brick and stone was prevalent in the early times of Greece, Sicily, and Italy. They used this for protection against the weather. It was later used over brick and concrete. Stucco was often made of lime, sand, and fine marble dust. Some forms would form a fine polish. This was usually used for decorating the inside of the house.
Concrete walls were used a lot in the construction of this time period. Walls were also built of masonry. There were five main types of facing used on concrete walls. The first type of facing that was used was opus quadratum. Opus quadratum was used to face normally more important buildings in the empire of Rome. This was the material used to make the outer layers of the Colosseum. Opus incertum was another type of facing used to face concrete and buildings. This was the facing used most commonly on concrete walls in the 1st and 2nd centuries BC. This type of facing usually had 3 to 4 inch studded irregular shaped stones. Opus reticulatum was the popular material used from 2 BC to roughly AD 117. The construction was similar to opus incertum but instead of irregular shaped pieces they used pyramid shaped pieces with a square foundation set diagonally and wedged into the concrete.