Roman houses evolved from the thatched-roof huts of the original Roman civilizations to the sumptuous villas of the late Empire. We can trace the evolution of these houses through allusions in literature, and especially through archeological remains. Roman houses varied depending not only on the era in which they were built, but also on their location. As well as those built in Italy, there were Roman houses built in Greece, Africa, Britain, and many other places.
The main room in the house was the atrium, a windowless room with a space in the ceiling (the compluvium) through which rain fell into the impluvium, a hollow space in the floor. There were alcoves on either side of the atrium, called alae, in which wax busts of ancestors were kept. There were four types of atrium: Tuscan (in which the roof was supported by two pairs of beams that crossed each other at right angles, tetrastylon (in which four pillars supported the roof beams at the corners of the compluvium), displuviatum (in which the roof sloped to the out walls), and testudinatum. Later the atrium was reduced to being a reception room.
The tablinum, the master's office or study, was where the master kept his arca (a heavy chest, sometimes chained to the floor, containing money and valuables). There were other rooms used for business: sometimes house owners converted front rooms into shops.
Sometimes larger houses had an open court in front of the door, called a vesibulum, with an ornamental pavement from the door to the street. In small houses this term applied to the narrow space between the door and the inner edge of the sidewalk.
There were numerous terms for the door in Roman times. Ostium included both the doorway and the door. It was also applied to either of these, but fores and janua are more precise words for the door itself. Doors opened inward; outer doors were provided with bolts and bars. Locks and keys were heavy and clumsy. In some houses a doorman or janitor was kept on duty. Inside houses, curtains were preferred to doors. Sometimes mosaics adorned the threshold, reading salve (good heath), nihil intret mali (may no evil enter), or cave canem (beware of dog). Some windows were provided with shutters, which slid in a framework on the outer wall. If these were in two parts, so that they moved in opposite directions, they were said to be junctae (joined).
The peristylum was an open court at the rear of the tablinum, planted with flowers, trees, and shrubs. In upper class houses, the peristyle was the center of household life. The culina or kitchen was the most important of the rooms about the peristyle. The dining room (triclinium) was not always close to the kitchen because slaves made carrying food fast and easy. Roman houses generally had many cubicula - small, scantily furnished sleeping rooms. There were also cubicula diurna, used for rest in the daytime (nighttime bedrooms were called cubicula nocturna or dormitoria). In the houses of many educated Romans there was a library (bibliotheca), where papyrus rolls were kept in cases or cabinets around the walls. There were other rooms, in addition to these: the sacrarium (a room with a shrine), oeci (rooms for the entertainment of large groups, exedrae (rooms furnished with permanent seats, used for entertainments), solarium (a sun deck), and perhaps pantries, storerooms, and cellars.
Roman houses had various methods for heating. In severe winter weather, portable stoves (braziers made of metal for holding hot coals) were used. Wealthy people sometimes had furnaces with chimneys. The fire was under the house, and warm air circulated in tile pipes or in hollow walls and floors without coming directy into the rooms. This heating arrangement was called a hypocaust, and it was used by moth baths in Italy.
Water was brought to houses by aqueducts from the mountains, sometimes for a long distance. Often houses had a tank in the upper story. Not many rooms had plumbing - slaves carried water as needed. The Cloaca Maxima, Rome's great sewer said to have been build in the time of the kings, continued to serve Rome until early in the present century.
Building materials in Rome varied greatly over time. Wood was commonly used for temporary structures. Permanent buildings were made of stone and unburned brick from early times. Walls of dressed stone were laid in regular courses. Tufa from Latium, was a dull color, but could be covered with fine white marble stucco to give it a brilliant finish. For ordinary houses, sun-dried bricks were largely used until the beginning of the first century BC. These were also covered with stucco. In classical time, cement was invented. Walls built of this durable, inexpensive material were called opus caementicium. Cement was also combined with crushed terra cotta to make a waterproof lining (opus Signinum) for cisterns. Although concerte walls were weatherproof, they were usually faced with stone or burned bricks. Walls of this type were called opus incertum (irregular work) if they were faced with stones with no regular size or shape, or opus reticulatum (network) if they were faced with uniform tufa stones. Bricks used for facing were triangular - no walls were built of brick alone.
The term for Roman floors was pavimentum - a name which originally referred to floors in small houses in which the ground in each room was smoothed, covered thickly with small pieces of stone, brick, tile or pottery, and pounded down solidly and smoothly with a heavy rammer. In better houses the floor was made of stone slabs fitted smoothly together. More elaborate houses had concrete floors, often with a mosaic surfaces. In the upper stories floors were made of wood, sometimes with a layer of concrete on top. Roman roofs varied, with some flat and some sloped. The earliest roof was a thatch of straw, later replaced by shingles and finally tiles.
Before the end of the Republic, the majority of the population lived in apartments called insulae (islands), a name originally applied to city blocks. These were sometimes six or seven stories high. Augustus limited their height to seventy feet; Nero, after the great fire in his reign, set a limit of sixty feet. Apartments were build poorly and cheaply and were often in danger of fire and collapse. The building was looked after by an insularius, a slave of the the owner.